原创-Mybatis

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Mybatis

1. Mybatis的引言

Mybatis是个基于java语⾔的持久层的框架,主要用来简化数据库的访问操作,内部封装
了原来的jdbc代码,替换了原有项目开发中的jdbc技术,他可以自动完成对象与关系的映射
(OR),极度简化了我们的开发,提高开发效率。

2. Jdbc中存在问题

1).大量的代码冗余 (处理结果集的时候存在大量的冗余)
2).不能完成数据库和实体的自动转换 (需要手动动封装实体,不能自定封装实体类)

3. Mybatis框架的开发思路

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4. Mybatis的环境搭建

4.1、书写连接相关的配置

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  • SqlMapConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<!-- mybatis的主配置文件 -->
<configuration>
    <!-- 配置环境 -->
    <environments default="mysql">
        <!-- 配置mysql的环境-->
        <environment id="mysql">
            <!-- 配置事务的类型-->
            <transactionManager type="JDBC"></transactionManager>
            <!-- 配置数据源(连接池) -->
            <dataSource type="POOLED">
                <!-- 配置连接数据库的4个基本信息 -->
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/eesy_mybatis"/>
                <property name="username" value="root"/>
                <property name="password" value="1234"/>
            </dataSource>
        </environment>
    </environments>

    <!-- 指定映射配置文件的位置,映射配置文件指的是每个dao独立的配置文件 -->
    <mappers>
        <mapper resource="com/itheima/dao/IUserDao.xml"/>
    </mappers>
</configuration>

4.2、编写测试类获取连接

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  • MybatisTest.java
package com.itheima.test;

import com.itheima.dao.IUserDao;
import com.itheima.domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.InputStream;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 * mybatis的入门案例
 */
public class MybatisTest {

    /**
     * 入门案例
     * @param args
     */
    public static void main(String[] args)throws Exception {
        //1.读取配置文件
        InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSessionFactory工厂
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(in);
        //3.使用工厂生产SqlSession对象
        SqlSession session = factory.openSession();
        //4.使用SqlSession创建Dao接口的代理对象
        IUserDao userDao = session.getMapper(IUserDao.class);
        //5.使用代理对象执行方法
        List<User> users = userDao.findAll();
        for(User user : users){
            System.out.println(user);
        }
        //6.释放资源
        session.close();
        in.close();
    }
}

4.3、建表

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4.4、开发实体类

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  • User.java
package com.itheima.domain;

import java.io.Serializable;
import java.util.Date;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class User implements Serializable{

    private Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", birthday=" + birthday +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

4.5、开发DAO接口

  • IUserDao.java
package com.itheima.dao;

import com.itheima.domain.User;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 *
 * 用户的持久层接口
 */
public interface IUserDao {

    /**
     * 查询所有操作
     * @return
     */
    List<User> findAll();
}

4.6、编写mapper配置文件

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  • IUserDao.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.dao.IUserDao">
    <!--配置查询所有-->
    <select id="findAll" resultType="com.itheima.domain.User">
        select * from user
    </select>
</mapper>

4.7 主配置文件中注册mapper配置文件

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4.8、测试DAO中的方法

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5. Mybatis中查询

5.1.查询所有数据

5.2.多个参数的查询

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6.Mybaits中的增删改

6.1.修改

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6.2.删除

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6.3.添加

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6.4代码

  • pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.itheima</groupId>
    <artifactId>day02_eesy_01mybatisCRUD</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
    </dependencies>
</project>
  • log4j.properties
# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n


  • jdbcConfig.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/eesy_mybatis
jdbc.username=root
jdbc.password=1234
  • SqlMapConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 配置properties
        可以在标签内部配置连接数据库的信息。也可以通过属性引用外部配置文件信息
        resource属性: 常用的
            用于指定配置文件的位置,是按照类路径的写法来写,并且必须存在于类路径下。
        url属性:
            是要求按照Url的写法来写地址
            URL:Uniform Resource Locator 统一资源定位符。它是可以唯一标识一个资源的位置。
            它的写法:
                http://localhost:8080/mybatisserver/demo1Servlet
                协议      主机     端口       URI

            URI:Uniform Resource Identifier 统一资源标识符。它是在应用中可以唯一定位一个资源的。
    -->
    <!-- <properties resource="jdbcConfig.properties">  </properties>-->
    <properties url="file:///D:/IdeaProjects/day02_eesy_01mybatisCRUD/src/main/resources/jdbcConfig.properties">
       <!-- <property name="driver" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://localhost:3306/eesy_mybatis"></property>
        <property name="username" value="root"></property>
        <property name="password" value="1234"></property>-->
    </properties>

    <!--使用typeAliases配置别名,它只能配置domain中类的别名 -->
    <typeAliases>
        <!--typeAlias用于配置别名。type属性指定的是实体类全限定类名。alias属性指定别名,当指定了别名就再区分大小写 
        <typeAlias type="com.itheima.domain.User" alias="user"></typeAlias>-->

        <!-- 用于指定要配置别名的包,当指定之后,该包下的实体类都会注册别名,并且类名就是别名,不再区分大小写-->
        <package name="com.itheima.domain"></package>
    </typeAliases>

    <!--配置环境-->
    <environments default="mysql">
        <!-- 配置mysql的环境-->
        <environment id="mysql">
            <!-- 配置事务 -->
            <transactionManager type="JDBC"></transactionManager>

            <!--配置连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"></property>
                <property name="url" value="${jdbc.url}"></property>
                <property name="username" value="${jdbc.username}"></property>
                <property name="password" value="${jdbc.password}"></property>
            </dataSource>
        </environment>
    </environments>
    <!-- 配置映射文件的位置 -->
    <mappers>
        <!--<mapper resource="com/itheima/dao/IUserDao.xml"></mapper>-->
        <!-- package标签是用于指定dao接口所在的包,当指定了之后就不需要在写mapper以及resource或者class了 -->
        <package name="com.itheima.dao"></package>
    </mappers>
</configuration>
  • User.java
package com.itheima.domain;

import java.io.Serializable;
import java.util.Date;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class User implements Serializable {

    private Integer userId;
    private String userName;
    private String userAddress;
    private String userSex;
    private Date userBirthday;

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserAddress() {
        return userAddress;
    }

    public void setUserAddress(String userAddress) {
        this.userAddress = userAddress;
    }

    public String getUserSex() {
        return userSex;
    }

    public void setUserSex(String userSex) {
        this.userSex = userSex;
    }

    public Date getUserBirthday() {
        return userBirthday;
    }

    public void setUserBirthday(Date userBirthday) {
        this.userBirthday = userBirthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", userAddress='" + userAddress + '\'' +
                ", userSex='" + userSex + '\'' +
                ", userBirthday=" + userBirthday +
                '}';
    }
}

  • QueryVo.java
package com.itheima.domain;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class QueryVo {

    private User user;

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }
}


  • IUserDao.java
package com.itheima.dao;

import com.itheima.domain.QueryVo;
import com.itheima.domain.User;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 *
 * 用户的持久层接口
 */
public interface IUserDao {

    /**
     * 查询所有用户
     * @return
     */
    List<User> findAll();

    /**
     * 保存用户
     * @param user
     */
    void saveUser(User user);

    /**
     * 更新用户
     * @param user
     */
    void updateUser(User user);

    /**
     * 根据Id删除用户
     * @param userId
     */
    void deleteUser(Integer userId);

    /**
     * 根据id查询用户信息
     * @param userId
     * @return
     */
    User findById(Integer userId);

    /**
     * 根据名称模糊查询用户信息
     * @param username
     * @return
     */
    List<User> findByName(String username);

    /**
     * 查询总用户数
     * @return
     */
    int findTotal();

    /**
     * 根据queryVo中的条件查询用户
     * @param vo
     * @return
     */
    List<User> findUserByVo(QueryVo vo);
}

  • IUserDao.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.dao.IUserDao">

    <!-- 配置 查询结果的列名和实体类的属性名的对应关系 -->
    <resultMap id="userMap" type="uSeR">
        <!-- 主键字段的对应 -->
        <id property="userId" column="id"></id>
        <!--非主键字段的对应-->
        <result property="userName" column="username"></result>
        <result property="userAddress" column="address"></result>
        <result property="userSex" column="sex"></result>
        <result property="userBirthday" column="birthday"></result>
    </resultMap>


    <!-- 查询所有 -->
    <select id="findAll" resultMap="userMap">
        <!--select id as userId,username as userName,address as userAddress,sex as userSex,birthday as userBirthday from user;-->
        select * from user;
    </select>

    <!-- 保存用户 -->
    <insert id="saveUser" parameterType="user">
        <!-- 配置插入操作后,获取插入数据的id -->
        <selectKey keyProperty="userId" keyColumn="id" resultType="int" order="AFTER">
            select last_insert_id();
        </selectKey>
        insert into user(username,address,sex,birthday)values(#{userName},#{userAddress},#{userSex},#{userBirthday});
    </insert>

    <!-- 更新用户 -->
    <update id="updateUser" parameterType="USER">
        update user set username=#{userName},address=#{userAddress},sex=#{userAex},birthday=#{userBirthday} where id=#{userId}
    </update>

    <!-- 删除用户-->
    <delete id="deleteUser" parameterType="java.lang.Integer">
        delete from user where id = #{uid}
    </delete>
    
    <!-- 根据id查询用户 -->
    <select id="findById" parameterType="INT" resultMap="userMap">
        select * from user where id = #{uid}
    </select>

    <!-- 根据名称模糊查询 -->
    <select id="findByName" parameterType="string" resultMap="userMap">
          select * from user where username like #{name}
        <!-- select * from user where username like '%${value}%'-->
  <!-- select * from user where username like concat('%',#{value},'%')-->
   </select>

    <!-- 获取用户的总记录条数 -->
    <select id="findTotal" resultType="int">
        select count(id) from user;
    </select>

    <!-- 根据queryVo的条件查询用户 -->
    <select id="findUserByVo" parameterType="com.itheima.domain.QueryVo" resultMap="userMap">
        select * from user where username like #{user.username}
    </select>
</mapper>
  • MybatisTest.java
package com.itheima.test;

import com.itheima.dao.IUserDao;
import com.itheima.domain.QueryVo;
import com.itheima.domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.Date;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 *
 * 测试mybatis的crud操作
 */
public class MybatisTest {

    private InputStream in;
    private SqlSession sqlSession;
    private IUserDao userDao;

    @Before//用于在测试方法执行之前执行
    public void init()throws Exception{
        //1.读取配置文件,生成字节输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.获取SqlSessionFactory
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        //3.获取SqlSession对象
        sqlSession = factory.openSession();
        //4.获取dao的代理对象
        userDao = sqlSession.getMapper(IUserDao.class);
    }

    @After//用于在测试方法执行之后执行
    public void destroy()throws Exception{
        //提交事务
        sqlSession.commit();
        //6.释放资源
        sqlSession.close();
        in.close();
    }

    /**
     * 测试查询所有
     */
    @Test
    public void testFindAll(){
        //5.执行查询所有方法
        List<User> users = userDao.findAll();
        for(User user : users){
            System.out.println(user);
        }

    }

    /**
     * 测试保存操作
     */
    @Test
    public void testSave(){
        User user = new User();
        user.setUserName("modify User property");
        user.setUserAddress("北京市顺义区");
        user.setUserSex("男");
        user.setUserBirthday(new Date());
        System.out.println("保存操作之前:"+user);
        //5.执行保存方法
        userDao.saveUser(user);

        System.out.println("保存操作之后:"+user);
    }

    /**
     * 测试更新操作
     */
    @Test
    public void testUpdate(){
        User user = new User();
        user.setUserId(50);
        user.setUserName("mybastis update user");
        user.setUserAddress("北京市顺义区");
        user.setUserSex("女");
        user.setUserBirthday(new Date());

        //5.执行保存方法
        userDao.updateUser(user);
    }

    /**
     * 测试删除操作
     */
    @Test
    public void testDelete(){
        //5.执行删除方法
        userDao.deleteUser(48);
    }

    /**
     * 测试删除操作
     */
    @Test
    public void testFindOne(){
        //5.执行查询一个方法
        User  user = userDao.findById(50);
        System.out.println(user);
    }

    /**
     * 测试模糊查询操作
     */
    @Test
    public void testFindByName(){
        //5.执行查询一个方法
        List<User> users = userDao.findByName("%王%");
//        List<User> users = userDao.findByName("王");
        for(User user : users){
            System.out.println(user);
        }
    }

    /**
     * 测试查询总记录条数
     */
    @Test
    public void testFindTotal(){
        //5.执行查询一个方法
        int count = userDao.findTotal();
        System.out.println(count);
    }


    /**
     * 测试使用QueryVo作为查询条件
     */
    @Test
    public void testFindByVo(){
        QueryVo vo = new QueryVo();
        User user = new User();
        user.setUserName("%王%");
        vo.setUser(user);
        //5.执行查询一个方法
        List<User> users = userDao.findUserByVo(vo);
        for(User u : users){
            System.out.println(u);
        }
    }
}

6.5 注解开发(增删查改)

  • pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.itheima</groupId>
    <artifactId>day04_eesy_03annotation_mybatis</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
    </dependencies>
</project>
  • jdbcConfig.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/eesy_mybatis
jdbc.username=root
jdbc.password=1234
  • log4j.properties
# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n


  • SqlMapConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 引入外部配置文件-->
    <properties resource="jdbcConfig.properties"></properties>
    <!--配置别名-->
    <typeAliases>
        <package name="com.itheima.domain"></package>
    </typeAliases>
    <!-- 配置环境-->
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"></property>
                <property name="url" value="${jdbc.url}"></property>
                <property name="username" value="${jdbc.username}"></property>
                <property name="password" value="${jdbc.password}"></property>
            </dataSource>
        </environment>
    </environments>
    <!-- 指定带有注解的dao接口所在位置 -->
    <mappers>
        <mapper class="com.itheima.dao.IUserDao"></mapper>
    </mappers>
</configuration>
  • User.java
package com.itheima.domain;

import java.io.Serializable;
import java.util.Date;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class User implements Serializable{

    private Integer id;
    private String username;
    private String address;
    private String sex;
    private Date birthday;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", address='" + address + '\'' +
                ", sex='" + sex + '\'' +
                ", birthday=" + birthday +
                '}';
    }
}

  • IUserDao.java
package com.itheima.dao;

import com.itheima.domain.User;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 * 在mybatis中针对,CRUD一共有四个注解
 *  @Select @Insert @Update @Delete
 */
public interface IUserDao {

    /**
     * 查询所有用户
     * @return
     */
    @Select("select * from user")
    List<User> findAll();

    /**
     * 保存用户
     * @param user
     */
    @Insert("insert into user(username,address,sex,birthday)values(#{username},#{address},#{sex},#{birthday})")
    void saveUser(User user);

    /**
     * 更新用户
     * @param user
     */
    @Update("update user set username=#{username},sex=#{sex},birthday=#{birthday},address=#{address} where id=#{id}")
    void updateUser(User user);

    /**
     * 删除用户
     * @param userId
     */
    @Delete("delete from user where id=#{id} ")
    void deleteUser(Integer userId);

    /**
     * 根据id查询用户
     * @param userId
     * @return
     */
    @Select("select * from user  where id=#{id} ")
    User findById(Integer userId);

    /**
     * 根据用户名称模糊查询
     * @param username
     * @return
     */
//    @Select("select * from user where username like #{username} ")
    @Select("select * from user where username like '%${value}%' ")
    List<User> findUserByName(String username);

    /**
     * 查询总用户数量
     * @return
     */
    @Select("select count(*) from user ")
    int findTotalUser();
}

  • AnnotationCRUDTest.java
package com.itheima.test;

import com.itheima.dao.IUserDao;
import com.itheima.domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.Date;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class AnnotationCRUDTest {
    private InputStream in;
    private SqlSessionFactory factory;
    private SqlSession session;
    private IUserDao userDao;

    @Before
    public  void init()throws Exception{
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        factory = new SqlSessionFactoryBuilder().build(in);
        session = factory.openSession();
        userDao = session.getMapper(IUserDao.class);
    }

    @After
    public  void destroy()throws  Exception{
        session.commit();
        session.close();
        in.close();
    }


    @Test
    public void testSave(){
        User user = new User();
        user.setUsername("mybatis annotation");
        user.setAddress("北京市昌平区");

        userDao.saveUser(user);
    }

    @Test
    public void testUpdate(){
        User user = new User();
        user.setId(57);
        user.setUsername("mybatis annotation update");
        user.setAddress("北京市海淀区");
        user.setSex("男");
        user.setBirthday(new Date());

        userDao.updateUser(user);
    }


    @Test
    public void testDelete(){
        userDao.deleteUser(51);
    }

    @Test
    public void testFindOne(){
        User user = userDao.findById(57);
        System.out.println(user);
    }


    @Test
    public  void testFindByName(){
//        List<User> users = userDao.findUserByName("%mybatis%");
        List<User> users = userDao.findUserByName("mybatis");
        for(User user : users){
            System.out.println(user);
        }
    }

    @Test
    public  void testFindTotal(){
        int total = userDao.findTotalUser();
        System.out.println(total);
    }
}

7. Mybatis工具类封装

在这里插入图片描述

8.添加修改细节

注意: Mybatis执行插入,修改时不允许出现空值,因此在插入修改时,想要使某个列的值可以为空,必须加jdbcType属性

8.1 添加修改细节

在这里插入图片描述

8.2 执行添加时

在这里插入图片描述

9.全部的jdbcType属性

在这里插入图片描述

10. 显示执行sql语句

  1. 引入log4j.properties
log4j.rootLogger=DEBUG, Console //根⽇志
log4j.appender.Console=org.apache.log4j.ConsoleAppender //控制台展示
log4j.appender.Console.layout=org.apache.log4j.PatternLayout //打印⽅式
log4j.appender.Console.layout.ConversionPattern=%d [%t] %-5p [%c] - %m%n //⽇
志格式
log4j.logger.com.baizhi.dao=DEBUG
注意:
1.log4j中存在两种日志。一种是项目中的根日志,二种种是项目中子日志
2.一般在项目中开启子日志即可
3. 日志级别: ERROR、WARN、INFO、DEBUG、TRACE

11、Mybatis中的别名

声明别名
在这里插入图片描述
使用别名
在这里插入图片描述

12.MyBatis中动态Sql

12.1. sql复用标签

在这里插入图片描述

12.2. if标签 动态拼接sql

在这里插入图片描述

12.3. where标签

在这里插入图片描述

12.4.choose when otherwise标签

在这里插入图片描述

12.5. set标签

在这里插入图片描述

12.6. trim标签

在这里插入图片描述

12.7. foreach遍历标签

在这里插入图片描述

12.7代码

  • pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.itheima</groupId>
    <artifactId>day03_eesy_02dynamicSQL</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
    </dependencies>

</project>
  • SqlMapConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 配置properties-->
    <properties resource="jdbcConfig.properties"></properties>

    <!--使用typeAliases配置别名,它只能配置domain中类的别名 -->
    <typeAliases>
        <package name="com.itheima.domain"></package>
    </typeAliases>

    <!--配置环境-->
    <environments default="mysql">
        <!-- 配置mysql的环境-->
        <environment id="mysql">
            <!-- 配置事务 -->
            <transactionManager type="JDBC"></transactionManager>

            <!--配置连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"></property>
                <property name="url" value="${jdbc.url}"></property>
                <property name="username" value="${jdbc.username}"></property>
                <property name="password" value="${jdbc.password}"></property>
            </dataSource>
        </environment>
    </environments>
    <!-- 配置映射文件的位置 -->
    <mappers>
        <package name="com.itheima.dao"></package>
    </mappers>
</configuration>
  • log4j.properties
# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

jdbcConfig.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/eesy_mybatis
jdbc.username=root
jdbc.password=1234

User.java

package com.itheima.domain;

import java.io.Serializable;
import java.util.Date;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class User implements Serializable {

    private Integer userId;
    private String userName;
    private String userAddress;
    private String userSex;
    private Date userBirthday;

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserAddress() {
        return userAddress;
    }

    public void setUserAddress(String userAddress) {
        this.userAddress = userAddress;
    }

    public String getUserSex() {
        return userSex;
    }

    public void setUserSex(String userSex) {
        this.userSex = userSex;
    }

    public Date getUserBirthday() {
        return userBirthday;
    }

    public void setUserBirthday(Date userBirthday) {
        this.userBirthday = userBirthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", userAddress='" + userAddress + '\'' +
                ", userSex='" + userSex + '\'' +
                ", userBirthday=" + userBirthday +
                '}';
    }
}

QueryVo.java

package com.itheima.domain;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class QueryVo {

    private User user;

    private List<Integer> ids;

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public List<Integer> getIds() {
        return ids;
    }

    public void setIds(List<Integer> ids) {
        this.ids = ids;
    }
}

  • IUserDao.java
package com.itheima.dao;

import com.itheima.domain.QueryVo;
import com.itheima.domain.User;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 *
 * 用户的持久层接口
 */
public interface IUserDao {

    /**
     * 查询所有用户
     * @return
     */
    List<User> findAll();


    /**
     * 根据id查询用户信息
     * @param userId
     * @return
     */
    User findById(Integer userId);

    /**
     * 根据名称模糊查询用户信息
     * @param username
     * @return
     */
    List<User> findByName(String username);


    /**
     * 根据queryVo中的条件查询用户
     * @param vo
     * @return
     */
    List<User> findUserByVo(QueryVo vo);

    /**
     * 根据传入参数条件
     * @param user 查询的条件:有可能有用户名,有可能有性别,也有可能有地址,还有可能是都有
     * @return
     */
    List<User> findUserByCondition(User user);

    /**
     * 根据queryvo中提供的id集合,查询用户信息
     * @param vo
     * @return
     */
    List<User> findUserInIds(QueryVo vo);
}

  • IUserDao.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.dao.IUserDao">

    <!-- 配置 查询结果的列名和实体类的属性名的对应关系 -->
    <resultMap id="userMap" type="uSeR">
        <!-- 主键字段的对应 -->
        <id property="userId" column="id"></id>
        <!--非主键字段的对应-->
        <result property="userName" column="username"></result>
        <result property="userAddress" column="address"></result>
        <result property="userSex" column="sex"></result>
        <result property="userBirthday" column="birthday"></result>
    </resultMap>

    <!-- 了解的内容:抽取重复的sql语句-->
    <sql id="defaultUser">
        select * from user
    </sql>

    <!-- 查询所有 -->
    <select id="findAll" resultMap="userMap">
        <include refid="defaultUser"></include>
    </select>

    <!-- 根据id查询用户 -->
    <select id="findById" parameterType="INT" resultMap="userMap">
        select * from user where id = #{uid}
    </select>

    <!-- 根据名称模糊查询 -->
    <select id="findByName" parameterType="string" resultMap="userMap">
          select * from user where username like #{name}
   </select>

    <!-- 根据queryVo的条件查询用户 -->
    <select id="findUserByVo" parameterType="com.itheima.domain.QueryVo" resultMap="userMap">
        select * from user where username like #{user.userName}
    </select>

    <!-- 根据条件查询
    <select id="findUserByCondition" resultMap="userMap" parameterType="user">
        select * from user where 1=1
        <if test="userName != null">
          and username = #{userName}
        </if>
        <if test="userSex != null">
            and sex = #{userSex}
        </if>
    </select>-->

    <select id="findUserByCondition" resultMap="userMap" parameterType="user">
        select * from user
        <where>
            <if test="userName != null">
                and username = #{userName}
            </if>
            <if test="userSex != null">
                and sex = #{userSex}
            </if>
        </where>
    </select>

    <!-- 根据queryvo中的Id集合实现查询用户列表 -->
    <select id="findUserInIds" resultMap="userMap" parameterType="queryvo">
        <include refid="defaultUser"></include>
        <where>
            <if test="ids != null and ids.size()>0">
                <foreach collection="ids" open="and id in (" close=")" item="uid" separator=",">
                    #{uid}
                </foreach>
            </if>
        </where>
    </select>
</mapper>

13. Mybatis处理一对一关联关系

13.1. 数据库

在这里插入图片描述

13.2. 实体类

在这里插入图片描述

13.3. 根据用户查找用户的身份信息

在这里插入图片描述

14. Mybatis处理一对多关联关系

14.1数据库模型

在这里插入图片描述

14.2实体类实现

在这里插入图片描述

14.3. 通过部门找员工

在这里插入图片描述

14.4通过员工找部门

在这里插入图片描述

14.5 代码

  • pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.itheima</groupId>
    <artifactId>day03_eesy_03one2many</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
    </dependencies>


</project>
  • log4j.properties
# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n


  • jdbcConfig.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/eesy_mybatis
jdbc.username=root
jdbc.password=1234
  • SqlMapConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 配置properties-->
    <properties resource="jdbcConfig.properties"></properties>

    <!--使用typeAliases配置别名,它只能配置domain中类的别名 -->
    <typeAliases>
        <package name="com.itheima.domain"></package>
    </typeAliases>

    <!--配置环境-->
    <environments default="mysql">
        <!-- 配置mysql的环境-->
        <environment id="mysql">
            <!-- 配置事务 -->
            <transactionManager type="JDBC"></transactionManager>

            <!--配置连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"></property>
                <property name="url" value="${jdbc.url}"></property>
                <property name="username" value="${jdbc.username}"></property>
                <property name="password" value="${jdbc.password}"></property>
            </dataSource>
        </environment>
    </environments>
    <!-- 配置映射文件的位置 -->
    <mappers>
        <package name="com.itheima.dao"></package>
    </mappers>
</configuration>
  • User.java
package com.itheima.domain;

import java.io.Serializable;
import java.util.Date;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class User implements Serializable {

    private Integer id;
    private String username;
    private String address;
    private String sex;
    private Date birthday;

    //一对多关系映射:主表实体应该包含从表实体的集合引用
    private List<Account> accounts;

    public List<Account> getAccounts() {
        return accounts;
    }

    public void setAccounts(List<Account> accounts) {
        this.accounts = accounts;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", address='" + address + '\'' +
                ", sex='" + sex + '\'' +
                ", birthday=" + birthday +
                '}';
    }
}

  • Account.java
package com.itheima.domain;

import java.io.Serializable;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class Account implements Serializable {

    private Integer id;
    private Integer uid;
    private Double money;

    //从表实体应该包含一个主表实体的对象引用
    private User user;

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getUid() {
        return uid;
    }

    public void setUid(Integer uid) {
        this.uid = uid;
    }

    public Double getMoney() {
        return money;
    }

    public void setMoney(Double money) {
        this.money = money;
    }

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", uid=" + uid +
                ", money=" + money +
                '}';
    }
}

  • AccountUser.java
package com.itheima.domain;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class AccountUser extends Account {

    private String username;
    private String address;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return super.toString()+"        AccountUser{" +
                "username='" + username + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

  • IUserDao.java
package com.itheima.dao;

import com.itheima.domain.User;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 *
 * 用户的持久层接口
 */
public interface IUserDao {

    /**
     * 查询所有用户,同时获取到用户下所有账户的信息
     * @return
     */
    List<User> findAll();


    /**
     * 根据id查询用户信息
     * @param userId
     * @return
     */
    User findById(Integer userId);


}

  • IUserDao.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.dao.IUserDao">

    <!-- 定义User的resultMap-->
    <resultMap id="userAccountMap" type="user">
        <id property="id" column="id"></id>
        <result property="username" column="username"></result>
        <result property="address" column="address"></result>
        <result property="sex" column="sex"></result>
        <result property="birthday" column="birthday"></result>
        <!-- 配置user对象中accounts集合的映射 -->
        <collection property="accounts" ofType="account">
            <id column="aid" property="id"></id>
            <result column="uid" property="uid"></result>
            <result column="money" property="money"></result>
        </collection>
    </resultMap>

    <!-- 查询所有 -->
    <select id="findAll" resultMap="userAccountMap">
        select * from user u left outer join account a on u.id = a.uid
    </select>

    <!-- 根据id查询用户 -->
    <select id="findById" parameterType="INT" resultType="user">
        select * from user where id = #{uid}
    </select>

</mapper>
  • IAccountDao.java
package com.itheima.dao;

import com.itheima.domain.Account;
import com.itheima.domain.AccountUser;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public interface IAccountDao {

    /**
     * 查询所有账户,同时还要获取到当前账户的所属用户信息
     * @return
     */
    List<Account> findAll();

    /**
     * 查询所有账户,并且带有用户名称和地址信息
     * @return
     */
    List<AccountUser> findAllAccount();
}

  • IAccountDao.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.dao.IAccountDao">

    <!-- 定义封装account和user的resultMap -->
    <resultMap id="accountUserMap" type="account">
        <id property="id" column="aid"></id>
        <result property="uid" column="uid"></result>
        <result property="money" column="money"></result>
        <!-- 一对一的关系映射:配置封装user的内容-->
        <association property="user" column="uid" javaType="user">
            <id property="id" column="id"></id>
            <result column="username" property="username"></result>
            <result column="address" property="address"></result>
            <result column="sex" property="sex"></result>
            <result column="birthday" property="birthday"></result>
        </association>
    </resultMap>

    <!-- 查询所有 -->
    <select id="findAll" resultMap="accountUserMap">
        select u.*,a.id as aid,a.uid,a.money from account a , user u where u.id = a.uid;
    </select>

    <!--查询所有账户同时包含用户名和地址信息-->
    <select id="findAllAccount" resultType="accountuser">
        select a.*,u.username,u.address from account a , user u where u.id = a.uid;
    </select>

</mapper>
  • UserTest.java
package com.itheima.test;

import com.itheima.dao.IUserDao;
import com.itheima.domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class UserTest {

    private InputStream in;
    private SqlSession sqlSession;
    private IUserDao userDao;

    @Before//用于在测试方法执行之前执行
    public void init()throws Exception{
        //1.读取配置文件,生成字节输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.获取SqlSessionFactory
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        //3.获取SqlSession对象
        sqlSession = factory.openSession(true);
        //4.获取dao的代理对象
        userDao = sqlSession.getMapper(IUserDao.class);
    }

    @After//用于在测试方法执行之后执行
    public void destroy()throws Exception{
        //提交事务
        // sqlSession.commit();
        //6.释放资源
        sqlSession.close();
        in.close();
    }

    /**
     * 测试查询所有
     */
    @Test
    public void testFindAll(){
        List<User> users = userDao.findAll();
        for(User user : users){
            System.out.println("-----每个用户的信息------");
            System.out.println(user);
            System.out.println(user.getAccounts());
        }
    }



}

  • AccountTest.java
package com.itheima.test;

import com.itheima.dao.IAccountDao;
import com.itheima.domain.Account;
import com.itheima.domain.AccountUser;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class AccountTest {

    private InputStream in;
    private SqlSession sqlSession;
    private IAccountDao accountDao;

    @Before//用于在测试方法执行之前执行
    public void init()throws Exception{
        //1.读取配置文件,生成字节输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.获取SqlSessionFactory
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        //3.获取SqlSession对象
        sqlSession = factory.openSession(true);
        //4.获取dao的代理对象
        accountDao = sqlSession.getMapper(IAccountDao.class);
    }

    @After//用于在测试方法执行之后执行
    public void destroy()throws Exception{
        //提交事务
        // sqlSession.commit();
        //6.释放资源
        sqlSession.close();
        in.close();
    }

    /**
     * 测试查询所有
     */
    @Test
    public void testFindAll(){
        List<Account> accounts = accountDao.findAll();
        for(Account account : accounts){
            System.out.println("--------每个account的信息------------");
            System.out.println(account);
            System.out.println(account.getUser());
        }
    }


    /**
     * 测试查询所有账户,同时包含用户名称和地址
     */
    @Test
    public void testFindAllAccountUser(){
        List<AccountUser> aus = accountDao.findAllAccount();
        for(AccountUser au : aus){
            System.out.println(au);
        }
    }
}

14.6 注解

  • pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.itheima</groupId>
    <artifactId>day04_eesy_04annoOne2Many</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
    </dependencies>

</project>
  • jdbcConfig.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/eesy_mybatis
jdbc.username=root
jdbc.password=1234
  • SqlMapConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 引入外部配置文件-->
    <properties resource="jdbcConfig.properties"></properties>
    <!--配置开启二级缓存-->
    <settings>
        <setting name="cacheEnabled" value="true"/>
    </settings>

    <!--配置别名-->
    <typeAliases>
        <package name="com.itheima.domain"></package>
    </typeAliases>
    <!-- 配置环境-->
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"></property>
                <property name="url" value="${jdbc.url}"></property>
                <property name="username" value="${jdbc.username}"></property>
                <property name="password" value="${jdbc.password}"></property>
            </dataSource>
        </environment>
    </environments>
    <!-- 指定带有注解的dao接口所在位置 -->
    <mappers>
       <package name="com.itheima.dao"></package>
    </mappers>
</configuration>
  • log4j.properties
# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n


  • Account.java
package com.itheima.domain;

import java.io.Serializable;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class Account implements Serializable {

    private Integer id;
    private Integer uid;
    private Double money;

    //多对一(mybatis中称之为一对一)的映射:一个账户只能属于一个用户
    private User user;

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getUid() {
        return uid;
    }

    public void setUid(Integer uid) {
        this.uid = uid;
    }

    public Double getMoney() {
        return money;
    }

    public void setMoney(Double money) {
        this.money = money;
    }

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", uid=" + uid +
                ", money=" + money +
                '}';
    }
}

  • User.java
package com.itheima.domain;

import java.io.Serializable;
import java.util.Date;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class User implements Serializable{

    private Integer userId;
    private String userName;
    private String userAddress;
    private String userSex;
    private Date userBirthday;

    //一对多关系映射:一个用户对应多个账户
    private List<Account> accounts;

    public List<Account> getAccounts() {
        return accounts;
    }

    public void setAccounts(List<Account> accounts) {
        this.accounts = accounts;
    }

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserAddress() {
        return userAddress;
    }

    public void setUserAddress(String userAddress) {
        this.userAddress = userAddress;
    }

    public String getUserSex() {
        return userSex;
    }

    public void setUserSex(String userSex) {
        this.userSex = userSex;
    }

    public Date getUserBirthday() {
        return userBirthday;
    }

    public void setUserBirthday(Date userBirthday) {
        this.userBirthday = userBirthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", userAddress='" + userAddress + '\'' +
                ", userSex='" + userSex + '\'' +
                ", userBirthday=" + userBirthday +
                '}';
    }
}

  • IUserDao.java
package com.itheima.dao;

import com.itheima.domain.User;
import org.apache.ibatis.annotations.*;
import org.apache.ibatis.mapping.FetchType;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 * 在mybatis中针对,CRUD一共有四个注解
 *  @Select @Insert @Update @Delete
 */
@CacheNamespace(blocking = true)
public interface IUserDao {

    /**
     * 查询所有用户
     * @return
     */
    @Select("select * from user")
    @Results(id="userMap",value={
            @Result(id=true,column = "id",property = "userId"),
            @Result(column = "username",property = "userName"),
            @Result(column = "address",property = "userAddress"),
            @Result(column = "sex",property = "userSex"),
            @Result(column = "birthday",property = "userBirthday"),
            @Result(property = "accounts",column = "id",
                    many = @Many(select = "com.itheima.dao.IAccountDao.findAccountByUid",
                                fetchType = FetchType.LAZY))
    })
    List<User> findAll();

    /**
     * 根据id查询用户
     * @param userId
     * @return
     */
    @Select("select * from user  where id=#{id} ")
    @ResultMap("userMap")
    User findById(Integer userId);

    /**
     * 根据用户名称模糊查询
     * @param username
     * @return
     */
    @Select("select * from user where username like #{username} ")
    @ResultMap("userMap")
    List<User> findUserByName(String username);


}

  • IAccountDao.java
package com.itheima.dao;

import com.itheima.domain.Account;
import org.apache.ibatis.annotations.One;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.mapping.FetchType;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public interface IAccountDao {

    /**
     * 查询所有账户,并且获取每个账户所属的用户信息
     * @return
     */
    @Select("select * from account")
    @Results(id="accountMap",value = {
            @Result(id=true,column = "id",property = "id"),
            @Result(column = "uid",property = "uid"),
            @Result(column = "money",property = "money"),
            @Result(property = "user",column = "uid",one=@One(select="com.itheima.dao.IUserDao.findById",fetchType= FetchType.EAGER))
    })
    List<Account> findAll();

    /**
     * 根据用户id查询账户信息
     * @param userId
     * @return
     */
    @Select("select * from account where uid = #{userId}")
    List<Account> findAccountByUid(Integer userId);
}
  • AccountTest.java
package com.itheima.test;

import com.itheima.dao.IAccountDao;
import com.itheima.domain.Account;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class AccountTest {
    private InputStream in;
    private SqlSessionFactory factory;
    private SqlSession session;
    private IAccountDao accountDao;

    @Before
    public  void init()throws Exception{
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        factory = new SqlSessionFactoryBuilder().build(in);
        session = factory.openSession();
        accountDao = session.getMapper(IAccountDao.class);
    }

    @After
    public  void destroy()throws  Exception{
        session.commit();
        session.close();
        in.close();
    }

    @Test
    public  void  testFindAll(){
        List<Account> accounts = accountDao.findAll();
        for(Account account : accounts){
            System.out.println("----每个账户的信息-----");
            System.out.println(account);
            System.out.println(account.getUser());
        }
    }



}


  • AnnotationCRUDTest.java
package com.itheima.test;

import com.itheima.dao.IUserDao;
import com.itheima.domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class AnnotationCRUDTest {
    private InputStream in;
    private SqlSessionFactory factory;
    private SqlSession session;
    private IUserDao userDao;

    @Before
    public  void init()throws Exception{
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        factory = new SqlSessionFactoryBuilder().build(in);
        session = factory.openSession();
        userDao = session.getMapper(IUserDao.class);
    }

    @After
    public  void destroy()throws  Exception{
        session.commit();
        session.close();
        in.close();
    }

    @Test
    public  void  testFindAll(){
        List<User> users = userDao.findAll();
//        for(User user : users){
//            System.out.println("---每个用户的信息----");
//            System.out.println(user);
//            System.out.println(user.getAccounts());
//        }
    }

    @Test
    public void testFindOne(){
        User user = userDao.findById(57);
        System.out.println(user);
    }


    @Test
    public  void testFindByName(){
        List<User> users = userDao.findUserByName("%mybatis%");
        for(User user : users){
            System.out.println(user);
        }
    }


}

  • SecondLevelCatchTest.java
package com.itheima.test;

import com.itheima.dao.IUserDao;
import com.itheima.domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class SecondLevelCatchTest {

    private InputStream in;
    private SqlSessionFactory factory;


    @Before
    public  void init()throws Exception{
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        factory = new SqlSessionFactoryBuilder().build(in);

    }

    @After
    public  void destroy()throws  Exception{

        in.close();
    }

    @Test
    public void testFindOne(){
        SqlSession session = factory.openSession();
        IUserDao userDao = session.getMapper(IUserDao.class);
        User user = userDao.findById(57);
        System.out.println(user);

        session.close();//释放一级缓存

        SqlSession session1 = factory.openSession();//再次打开session
        IUserDao userDao1 = session1.getMapper(IUserDao.class);
        User user1 = userDao1.findById(57);
        System.out.println(user1);


        session1.close();

    }
}

15. Mybatis处理多对多关联关系

多对多在数据库的设计里也是使用两个一对多实现的
实体类在开发时两边都是集合类型的关系属性
mapper文件在维护时都使用 <collection 标签>

15.1 代码

  • pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.itheima</groupId>
    <artifactId>day03_eesy_04many2many</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
    </dependencies>

</project>
  • log4j.properties
# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

  • jdbcConfig.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/eesy_mybatis
jdbc.username=root
jdbc.password=1234
  • SqlMapConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 配置properties-->
    <properties resource="jdbcConfig.properties"></properties>

    <!--使用typeAliases配置别名,它只能配置domain中类的别名 -->
    <typeAliases>
        <package name="com.itheima.domain"></package>
    </typeAliases>

    <!--配置环境-->
    <environments default="mysql">
        <!-- 配置mysql的环境-->
        <environment id="mysql">
            <!-- 配置事务 -->
            <transactionManager type="JDBC"></transactionManager>

            <!--配置连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"></property>
                <property name="url" value="${jdbc.url}"></property>
                <property name="username" value="${jdbc.username}"></property>
                <property name="password" value="${jdbc.password}"></property>
            </dataSource>
        </environment>
    </environments>
    <!-- 配置映射文件的位置 -->
    <mappers>
        <package name="com.itheima.dao"></package>
    </mappers>
</configuration>
  • User.java
package com.itheima.domain;

import java.io.Serializable;
import java.util.Date;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class User implements Serializable {

    private Integer id;
    private String username;
    private String address;
    private String sex;
    private Date birthday;

    //多对多的关系映射:一个用户可以具备多个角色
    private List<Role> roles;

    public List<Role> getRoles() {
        return roles;
    }

    public void setRoles(List<Role> roles) {
        this.roles = roles;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", address='" + address + '\'' +
                ", sex='" + sex + '\'' +
                ", birthday=" + birthday +
                '}';
    }
}

  • Role.java
package com.itheima.domain;

import java.io.Serializable;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class Role implements Serializable {

    private Integer roleId;
    private String roleName;
    private String roleDesc;

    //多对多的关系映射:一个角色可以赋予多个用户
    private List<User> users;

    public List<User> getUsers() {
        return users;
    }

    public void setUsers(List<User> users) {
        this.users = users;
    }

    public Integer getRoleId() {
        return roleId;
    }

    public void setRoleId(Integer roleId) {
        this.roleId = roleId;
    }

    public String getRoleName() {
        return roleName;
    }

    public void setRoleName(String roleName) {
        this.roleName = roleName;
    }

    public String getRoleDesc() {
        return roleDesc;
    }

    public void setRoleDesc(String roleDesc) {
        this.roleDesc = roleDesc;
    }

    @Override
    public String toString() {
        return "Role{" +
                "roleId=" + roleId +
                ", roleName='" + roleName + '\'' +
                ", roleDesc='" + roleDesc + '\'' +
                '}';
    }
}

IUserDao.java

package com.itheima.dao;

import com.itheima.domain.User;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 *
 * 用户的持久层接口
 */
public interface IUserDao {

    /**
     * 查询所有用户,同时获取到用户下所有账户的信息
     * @return
     */
    List<User> findAll();


    /**
     * 根据id查询用户信息
     * @param userId
     * @return
     */
    User findById(Integer userId);


}

IUserDao.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.dao.IUserDao">

    <!-- 定义User的resultMap-->
    <resultMap id="userMap" type="user">
        <id property="id" column="id"></id>
        <result property="username" column="username"></result>
        <result property="address" column="address"></result>
        <result property="sex" column="sex"></result>
        <result property="birthday" column="birthday"></result>
        <!-- 配置角色集合的映射 -->
        <collection property="roles" ofType="role">
            <id property="roleId" column="rid"></id>
            <result property="roleName" column="role_name"></result>
            <result property="roleDesc" column="role_desc"></result>
        </collection>
    </resultMap>

    <!-- 查询所有 -->
    <select id="findAll" resultMap="userMap">
        select u.*,r.id as rid,r.role_name,r.role_desc from user u
         left outer join user_role ur  on u.id = ur.uid
         left outer join role r on r.id = ur.rid
    </select>

    <!-- 根据id查询用户 -->
    <select id="findById" parameterType="INT" resultType="user">
        select * from user where id = #{uid}
    </select>

</mapper>

IRoleDao.java

package com.itheima.dao;

import com.itheima.domain.Role;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public interface IRoleDao {

    /**
     * 查询所有角色
     * @return
     */
    List<Role> findAll();
}

IRoleDao.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.dao.IRoleDao">

    <!--定义role表的ResultMap-->
    <resultMap id="roleMap" type="role">
        <id property="roleId" column="rid"></id>
        <result property="roleName" column="role_name"></result>
        <result property="roleDesc" column="role_desc"></result>
        <collection property="users" ofType="user">
            <id column="id" property="id"></id>
            <result column="username" property="username"></result>
            <result column="address" property="address"></result>
            <result column="sex" property="sex"></result>
            <result column="birthday" property="birthday"></result>
        </collection>
    </resultMap>

    <!--查询所有-->
    <select id="findAll" resultMap="roleMap">
       select u.*,r.id as rid,r.role_name,r.role_desc from role r
        left outer join user_role ur  on r.id = ur.rid
        left outer join user u on u.id = ur.uid
    </select>
</mapper>
  • UserTest.java
package com.itheima.test;

import com.itheima.dao.IUserDao;
import com.itheima.domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class UserTest {

    private InputStream in;
    private SqlSession sqlSession;
    private IUserDao userDao;

    @Before//用于在测试方法执行之前执行
    public void init()throws Exception{
        //1.读取配置文件,生成字节输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.获取SqlSessionFactory
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        //3.获取SqlSession对象
        sqlSession = factory.openSession(true);
        //4.获取dao的代理对象
        userDao = sqlSession.getMapper(IUserDao.class);
    }

    @After//用于在测试方法执行之后执行
    public void destroy()throws Exception{
        //提交事务
        // sqlSession.commit();
        //6.释放资源
        sqlSession.close();
        in.close();
    }

    /**
     * 测试查询所有
     */
    @Test
    public void testFindAll(){
        List<User> users = userDao.findAll();
        for(User user : users){
            System.out.println("-----每个用户的信息------");
            System.out.println(user);
            System.out.println(user.getRoles());
        }
    }



}

  • RoleTest.java
package com.itheima.test;

import com.itheima.dao.IRoleDao;
import com.itheima.domain.Role;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class RoleTest {

    private InputStream in;
    private SqlSession sqlSession;
    private IRoleDao roleDao;

    @Before//用于在测试方法执行之前执行
    public void init()throws Exception{
        //1.读取配置文件,生成字节输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.获取SqlSessionFactory
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        //3.获取SqlSession对象
        sqlSession = factory.openSession(true);
        //4.获取dao的代理对象
        roleDao = sqlSession.getMapper(IRoleDao.class);
    }

    @After//用于在测试方法执行之后执行
    public void destroy()throws Exception{
        //提交事务
        // sqlSession.commit();
        //6.释放资源
        sqlSession.close();
        in.close();
    }

    /**
     * 测试查询所有
     */
    @Test
    public void testFindAll(){
        List<Role> roles = roleDao.findAll();
        for(Role role : roles){
            System.out.println("---每个角色的信息----");
            System.out.println(role);
            System.out.println(role.getUsers());
        }
    }

}

17. 常用配置

  • db.properties
jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/Yxjmydatabase?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
jdbc.username=root
jdbc.password=123456
  • log4j.properties
# Global logging configuration
log4j.rootLogger=ERROR,stdout
# MyBatis logging configuration.
log4j.logger.yxj.com.itheima=DEBUG
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
一对一,在任意一方引入对方主键作为外键;
一对多,在"多"的一方,添加"一"的一方的主键外键
多对多,产生中间关系表,引入两张表的主键作为外键,两个主键成为联合
主键.

16.图片

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本文链接http://www.taodudu.cc/news/show-1944898.html