一个list<Map>里map其中的一个字段的值相同,如何判断这个字段相同,就把这个map的其他字段存入另一个map中

引用：https://www.cnblogs.com/dupengfei-summer/p/9283156.html

package util;

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

public class ListMapUtil {
    public static void main(String[] args) {
        mapData();
    }

    public static void mapData() {
        Map map1 = new HashMap<>();
        Map map2 = new HashMap<>();
        Map map3 = new HashMap<>();
        Map map4 = new HashMap<>();
        Map map5 = new HashMap<>();
        Map map6 = new HashMap<>();
        Map map7 = new HashMap<>();

        map1.put("maId", 17);
        map1.put("loginNum", 396);

        map2.put("maId", 17);
        map2.put("shareGoodsOrderNum", 396);

        map3.put("maId", 39);
        map3.put("loginNum", 3);

        map4.put("maId", 239);
        map4.put("loginNum", 1323);

        map5.put("maId", 17);
        map5.put("orderNum", 1);

        map6.put("maId", 39);
        map6.put("loginNum", 3);

        map7.put("maId", 17);
        map7.put("addFamerInfoNum", 24);

        List<Map> list = new ArrayList();
        list.add(map1);
        list.add(map2);
        list.add(map3);
        list.add(map4);
        list.add(map5);
        list.add(map6);
        list.add(map7);
        System.out.println("原本的list" + list);

        //合并相同maid的map成为一个map
        //获取一个map,判断另一个map中的key有没有相同的，有就合并，合并完后

        for (int i = 0; i < list.size(); i++) {
            Map map = list.get(i);
            // 从当前项的下一项开始检查
            for (int j = i + 1; j < list.size(); j++) {
                Map<String, Object> childMap = list.get(j);
                // ID 相等
                if (null != map.get("maId") & null != childMap.get("maId")) {
                    if (map.get("maId").equals(childMap.get("maId"))) {
                        // 合并，此处需要先 remove
                        list.remove(childMap);
                        map.putAll(childMap);
                    }
                }

            }
        }
        System.out.println("合并后的list:" + list);


    }
   
}

输出值：

原本的list[{maId=17, loginNum=396}, {shareGoodsOrderNum=396, maId=17}, {maId=39, loginNum=3}, {maId=239, loginNum=1323}, {orderNum=1, maId=17}, {maId=39, loginNum=3}, {maId=17, addFamerInfoNum=24}]
合并后的list:[{shareGoodsOrderNum=396, orderNum=1, maId=17, loginNum=396, addFamerInfoNum=24}, {maId=239, loginNum=1323}, {maId=39, loginNum=3}]