聯(lián)合MyBatis，由Map獲取

專注于為中小企業(yè)提供做網(wǎng)站、成都網(wǎng)站建設(shè)服務(wù),電腦端+手機端+微信端的三站合一,更高效的管理,為中小企業(yè)九原免費做網(wǎng)站提供優(yōu)質(zhì)的服務(wù)。我們立足成都，凝聚了一批互聯(lián)網(wǎng)行業(yè)人才，有力地推動了上千多家企業(yè)的穩(wěn)健成長，幫助中小企業(yè)通過網(wǎng)站建設(shè)實現(xiàn)規(guī)模擴充和轉(zhuǎn)變。

源碼如下

package com.zl.demo;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Java遞歸獲取TreeJson
 * @author ZhangLi
 * @date 2019年6月18日 上午11:10:45
 * @WeiXin zl4828
 * @備注 沫沫金原創(chuàng)提供，僅供參考
 */
public class TreeJson {
    public static void main(String[] args) {
        TreeJson treeJson = new TreeJson();
        treeJson.treeMap.add(new HashMap(){{
            put("ID","0");
            put("NAME","根節(jié)點");
            put("PID","null");
        }});
        treeJson.treeMap.add(new HashMap(){{
            put("ID","1");
            put("NAME","節(jié)點1");
            put("PID","0");
        }});
        treeJson.treeMap.add(new HashMap(){{
            put("ID","2");
            put("NAME","節(jié)點2");
            put("PID","0");
        }});
        treeJson.treeMap.add(new HashMap(){{
            put("ID","3");
            put("NAME","節(jié)點3");
            put("PID","0");
        }});
        treeJson.treeMap.add(new HashMap(){{
            put("ID","11");
            put("NAME","節(jié)點11");
            put("PID","1");
        }});
        treeJson.treeMap.add(new HashMap(){{
            put("ID","12");
            put("NAME","節(jié)點12");
            put("PID","1");
        }});
        treeJson.treeMap.add(new HashMap(){{
            put("ID","13");
            put("NAME","節(jié)點13");
            put("PID","1");
        }});
        System.out.println(treeJson.recursiveTree("0"));
    }

    private List> treeMap = new ArrayList>();  //全局變量

    /**
     * 遞歸算法解析成樹形結(jié)構(gòu)
     * @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;
    }

    /**
     * 根據(jù)pid查詢節(jié)點對象
     */
    public Map getNodeById(String pid){
        for (Map node : treeMap) {
            if(null != pid){
                if (pid.equals(node.get("ID"))) {
                    return node;
                }
            }
        }
        return null;
    }
    /**
     * 根據(jù)父節(jié)點pid獲取所有了節(jié)點
     */
    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;
    }

}

應(yīng)用場景
例如，Echarts樹形圖形

注意，使用JSON轉(zhuǎn)換

{
    name: '根節(jié)點',
    pid: null,
    id: 0,
    children: [{
        name: '節(jié)點1',
        pid: 0,
        id: 1,
        children: [{
            name: '節(jié)點11',
            pid: 1,
            id: 11,
            children: []
        }, {
            name: '節(jié)點12',
            pid: 1,
            id: 12,
            children: []
        }, {
            name: '節(jié)點13',
            pid: 1,
            id: 13,
            children: []
        }]
    }, {
        name: '節(jié)點2',
        pid: 0,
        id: 2,
        children: []
    }, {
        name: '節(jié)點3',
        pid: 0,
        id: 3,
        children: []
    }]
};

以上，拷貝本地運行，任意應(yīng)用。