mybatis-plus 下建立 联合查询，用xml

 

在 resource mapper下建立 user.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="cn.taotao.dao.UserDao">
<resultMap id="MyUser" type="cn.taotao.domain.User">
    <id column="id" jdbcType="INTEGER" property="id"></id>
    <result column="name" jdbcType="VARCHAR" property="name"></result>
    <result column="pid" jdbcType="INTEGER" property="pid"></result>
    <association property="pUser" javaType="cn.taotao.domain.User">
        <id column="pid" property="id"></id>
        <result column="pname" jdbcType="VARCHAR" property="name"></result>

    </association>
</resultMap>


<select id="getOne" resultType="cn.taotao.domain.User">
    select * from tbl_test where id = #{id}

</select>

<select id="getAll" resultType="cn.taotao.domain.User">
    select * from tbl_test
</select>

<!--    @Select("select a.id,a.name,b.name as pname,a.pid as pid   from tbl_test as a,tbl_test as b where a.id =${ew} and a.pid = b.id")-->
<!--    @Results({-->
<!--    @Result(id =true,property = "id",column = "id"),-->
<!--    @Result(property = "name" ,column = "name"),-->
<!--    @Result(javaType = User.class,property = "pUser" ,column = "pid",one=@One(select="cn.taotao.UserDao.getOne"))-->
<!--    })-->

    <select id="findAll" resultMap="MyUser">

        select a.id,a.name,b.name as pname,a.pid as pid   from tbl_test as a,tbl_test as b where a.pid > ${ew} and a.pid = b.id
    </select>


</mapper>

dao

public interface UserDao extends BaseMapper<User> {


    List<User> findAll(@Param("ew") Integer id);


    User getOne(@Param("id") Integer id);

    List<User> getAll();
}

yml

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: xxxxx
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  mapper-locations: classpath*:/mapper/**/*.xml

返回结果