以下为Mybatis映射文件

<?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.org.mabatis.testDao">
 
    <resultMap id="BaseTreeResultMap" type="com.org.model.NodeModel">
        <id property="id" jdbcType="VARCHAR" column="id"/>
        <result property="node" jdbcType="VARCHAR" column="node"/>
        <result property="p_node_id" jdbcType="VARCHAR" column="pNodeId"/>
        <collection property="subNode" ofType="nodeModel" column="id" jdbcType="java.util.ArrayList"
        select="getSubNode"/>
    </resultMap>
 
    <resultMap id="SubTreeResultMap" type="com.org.model.NodeModel">
        <id property="id" jdbcType="VARCHAR" column="id"/>
        <result property="node" jdbcType="VARCHAR" column="node"/>
        <result property="p_node_id" jdbcType="VARCHAR" column="pNodeId"/>
        <collection property="subNode" ofType="nodeModel" column="id" jdbcType="java.util.ArrayList"
                    select="getSubNode"/>
    </resultMap>
 
    <sql id="Base_Column">
        id, node, p_node_id
    </sql>
 
    <select id="getBaseNode" resultMap="BaseTreeResultMap">
        select
        <include refid="Base_Column"/>
        from sys_node
        where p_node_id = '0'
    </select>
 
    <select id="getSubNode">
        select
        <include refid="Base_Column"/>
        from sys_node
        where p_node_id = #{id}
    </select>
</mapper>

以下为结果json

[
    {
        "id":"1",
        "node":"一级节点",
        "pNodeId":"0",
        "subNode":[
            {
                "id":"2",
                "node":"二级节点",
                "pNodeId":"1",
                "subNode":[
                    {
                        "id":"3",
                        "node":"三级节点",
                        "pNodeId":"2",
                        "subNode":[
                            {
                                "id":"4",
                                "node":"四级节点",
                                "pNodeId":"3",
                                "subNode":[
 
                                ]
                            }
                        ]
                    }
                ]
            }
        ]
    },
    {
        "id":"5",
        "node":"一级节点",
        "pNodeId":"0",
        "subNode":[
            {
                "id":"6",
                "node":"二级节点",
                "pNodeId":"5",
                "subNode":[
                    {
                        "id":"7",
                        "node":"三级节点",
                        "pNodeId":"6",
                        "subNode":[
                            {
                                "id":"8",
                                "node":"四级节点",
                                "pNodeId":"7",
                                "subNode":[
 
                                ]
                            }
                        ]
                    }
                ]
            }
        ]
    }

]