SprintBoot Mapper 树形查询

DeptMapper.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.zhen.mp.mapper.DeptMapper">
    <resultMap id="treeMap" type="com.zhen.mp.dto.dept.DeptTreeDto">
        <id column="id" property="id"/>
        <result column="p_id" property="ppId" />
        <result column="name" property="name" />
        <result column="sort" property="sort" />
        <collection column="id" property="sonNode" javaType="java.util.ArrayList"  ofType="com.zhen.mp.dto.dept.DeptTreeDto" select="getNextTree"/>
    </resultMap>
    <select id="getTree" resultMap="treeMap">
        select * from dept where p_id is null;
    </select>
    <select id="getNextTree" resultMap="treeMap">
        select * from dept where p_id = #{id}
    </select>
</mapper>

DeptMapper.java

package com.zhen.mp.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.zhen.mp.bean.Dept;
import com.zhen.mp.dto.dept.DeptTreeDto;
import org.springframework.stereotype.Repository;
import java.util.List;
@Repository
public interface DeptMapper extends BaseMapper<Dept> {
    List<DeptTreeDto> getTree();
    List<DeptTreeDto> getNextTree();
}

Dept.java

package com.zhen.mp.bean;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import com.baomidou.mybatisplus.extension.activerecord.Model;
import lombok.Data;
@Data
@TableName("dept")
public class Dept extends Model {
    @TableId(type = IdType.AUTO)
    private Long id;
    private Long pId;
    private String name;
    private Integer sort;
}

DeptTreeDto.java

package com.zhen.mp.dto.dept;
import lombok.Data;
import java.util.List;
@Data
public class DeptTreeDto {
    private Long id;
    private Long ppId;
    private String name;
    private Integer sort;
    private List<DeptTreeDto> sonNode;
}

SprintBoot Mapper 树形查询

原文：https://www.cnblogs.com/yanzhen/p/12724999.html