Java递归获得TreeJson

联合MyBatis，由Map获取

源码如下

package com.zl.demo;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;/** * Java递归获取TreeJson * @author ZhangLi * @date 2019年6月18日 上午11:10:45 * @WeiXin zl4828 * @备注 沫沫金原创提供，仅供参考 */public class TreeJson {    public static void main(String[] args) {        TreeJson treeJson = new TreeJson();        treeJson.treeMap.add(new HashMap(){{            put("ID","0");            put("NAME","根节点");            put("PID","null");        }});        treeJson.treeMap.add(new HashMap(){{            put("ID","1");            put("NAME","节点1");            put("PID","0");        }});        treeJson.treeMap.add(new HashMap(){{            put("ID","2");            put("NAME","节点2");            put("PID","0");        }});        treeJson.treeMap.add(new HashMap(){{            put("ID","3");            put("NAME","节点3");            put("PID","0");        }});        treeJson.treeMap.add(new HashMap(){{            put("ID","11");            put("NAME","节点11");            put("PID","1");        }});        treeJson.treeMap.add(new HashMap(){{            put("ID","12");            put("NAME","节点12");            put("PID","1");        }});        treeJson.treeMap.add(new HashMap(){{            put("ID","13");            put("NAME","节点13");            put("PID","1");        }});        System.out.println(treeJson.recursiveTree("0"));    }    private List> treeMap = new ArrayList>();  //全局变量    /**     * 递归算法解析成树形结构     * @param pid     */    public Map recursiveTree(String pid) {        Map node = getNodeById(pid);        List> childrenList = new ArrayList>();        if(null==node){            return node;        }        List> childTreeNodes  = getChildTreeById(pid);        for(Map child : childTreeNodes){            Map n = recursiveTree(String.valueOf(child.get("ID")));            childrenList.add(n);        }        node.put("children",childrenList);        return node;    }    /**     * 根据pid查询节点对象     */    public Map getNodeById(String pid){        for (Map node : treeMap) {            if(null != pid){                if (pid.equals(node.get("ID"))) {                    return node;                }            }        }        return null;    }    /**     * 根据父节点pid获取所有了节点     */    public List> getChildTreeById(String pid){        List> list = new ArrayList>();        if(null != treeMap){            for (Map node : treeMap) {                if(null != pid){                    if (pid.equals(node.get("PID"))) {                        list.add(node);                    }                }            }        }        return list;    }}

应用场景
例如，Echarts树形图形

注意，使用JSON转换

{    name: '根节点',    pid: null,    id: 0,    children: [{        name: '节点1',        pid: 0,        id: 1,        children: [{            name: '节点11',            pid: 1,            id: 11,            children: []        }, {            name: '节点12',            pid: 1,            id: 12,            children: []        }, {            name: '节点13',            pid: 1,            id: 13,            children: []        }]    }, {        name: '节点2',        pid: 0,        id: 2,        children: []    }, {        name: '节点3',        pid: 0,        id: 3,        children: []    }]};

以上，拷贝本地运行，任意应用。