Mybatis中从角色到用户的多对多操作

role表：

User表：

user_role表：

Role类：

package com.qublog.domain;

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

public class Role implements Serializable {
    private Integer roleId;
    private String roleName;
    private String roleDesc;

    //多对多关系映射，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 + '\'' +
                '}';
    }
}

User类：

package com.qublog.domain;

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

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 +
                '}';
    }
}

RoleDao接口：

package com.qublog.dao;

import com.qublog.domain.Role;

import java.util.List;

public interface RoleDao {
    //查询所有角色
    List<Role> findAll();
}

UserDao接口：

package com.qublog.dao;


import com.qublog.domain.User;

import java.util.List;

//用户的持久层接口
public interface UserDao {

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

RoleDao.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.qublog.dao.RoleDao">
    <!-- 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 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>
        </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 ur.rid=r.id
         left outer join user u on u.id=ur.uid
    </select>
</mapper>

UserDao.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.qublog.dao.UserDao">
    <!-- 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>
    </resultMap>

    <!-- 配置查询所有 -->
    <select id="findAll" resultMap="userAccountMap">
        select u.*, a.id as aid, a.uid, a.money from user u left outer join account a on a.uid=u.id;
    </select>

</mapper>

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>
        <!-- typeAlias用于配置别名，type属性指定的是实体类全限定类名，alias指定别名，当指定了别名就不再区分大小写 -->
        <!-- 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.qublog.domain"></package>
    </typeAliases>

    <!-- 配置环境 -->
    <environments default="mysql">
        <!-- 配置mysql的环境 -->
        <environment id="mysql">
            <!-- 配置事务类型 -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- 配置连接池 -->
            <dataSource type="POOLED">
                <!-- 配置连接数据库的基本信息 -->
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>

    <!-- 用注解时使用class属性指定被注解的dao全限定类名 -->
    <mappers>
        <!-- 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再写mapper以及resource或者class了 -->
        <package name="com.qublog.dao"></package>
    </mappers>
</configuration>

RoleTest类：

package com.qublog.test;


import com.qublog.dao.RoleDao;
import com.qublog.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;

public class RoleTest {
    private InputStream in = null;
    private SqlSession sqlSession = null;
    RoleDao roleDao = null;

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

    @Test
    public void testFindAll() throws Exception {
        //执行查询所有方法
        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());
        }
    }
}

结果：