MybatisPlus 对象嵌套关联查询一对多List集合查询

mybatis嵌套关联查询如下：

由于我的是一对集合查询，所以我有两个类。

@Data
@TableName("tb_user")
public class User {
    @TableId(type= IdType.INPUT)
    private String id;
    @TableField("user_name")
    private String username;
    private String password;
    private String name;
    private String email;
    private int age;
    private ArrayList<Authority> list;
}

权限类

@Data
@TableName
public class Authority {
    @TableId(type = IdType.INPUT)
    @TableField("aid")
    private int id;
    @TableId("aname")
    private String name;
}

测试类

 @Test
    public void ManyToMany(){
        User user = userMapper.selectAuthorityById(1);
        ArrayList <Authority> list = user.getList();
        System.out.println(user);
        for (Authority authority : list) {
            System.out.println("所对应权限为"+authority.getName());
        }
    }

springboot项目的依赖

       <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
        <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.26</version>
    </dependency>
        <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
        <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
       <!--mybatis plus 起步依赖-->
        <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>3.4.0</version>
    </dependency>

这下面就是我xml文件里面怎么写的嵌套查询语句

<mapper namespace="com.itheima.mybatisplus.mapper.UserMapper">
    <!--返回的对象为authority-->
    <resultMap id="authority" type="com.itheima.mybatisplus.domain.User">
        <id column="id" property="id"/>
        <id column="password" property="password"/>
        <id column="age" property="age"/>
        <id column="email" property="email"/>
        <id column="name" property="name"/>
        <id column="user_name" property="username"/>
      <collection property="list"
                  ofType="com.itheima.mybatisplus.domain.Authority">
          <id property="id" column="aid"/>
          <id property="name" column="aname"/>
      </collection>


	<select id="selectAuthorityById" parameterType="int" resultMap="authority">
       SELECT * FROM
         authority a,tb_user t,user_authority ua
         WHERE a.aid=ua.authority_id
         AND t.id=ua.user_id
         AND t.id=#{id}
    </select>

数据库的配置我就不放了,直接编写就可以了,看会下面这个xml配置就可以了