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

 1 package util;
 2 
 3 import java.util.ArrayList;
 4 import java.util.HashMap;
 5 import java.util.List;
 6 import java.util.Map;
 7 
 8 public class ListMapUtil {
 9     public static void main(String[] args) {
10         mapData();
11     }
12 
13     public static void mapData() {
14         Map map1 = new HashMap<>();
15         Map map2 = new HashMap<>();
16         Map map3 = new HashMap<>();
17         Map map4 = new HashMap<>();
18         Map map5 = new HashMap<>();
19         Map map6 = new HashMap<>();
20         Map map7 = new HashMap<>();
21 
22         map1.put("maId", 17);
23         map1.put("loginNum", 396);
24 
25         map2.put("maId", 17);
26         map2.put("shareGoodsOrderNum", 396);
27 
28         map3.put("maId", 39);
29         map3.put("loginNum", 3);
30 
31         map4.put("maId", 239);
32         map4.put("loginNum", 1323);
33 
34         map5.put("maId", 17);
35         map5.put("orderNum", 1);
36 
37         map6.put("maId", 39);
38         map6.put("loginNum", 3);
39 
40         map7.put("maId", 17);
41         map7.put("addFamerInfoNum", 24);
42 
43         List<Map> list = new ArrayList();
44         list.add(map1);
45         list.add(map2);
46         list.add(map3);
47         list.add(map4);
48         list.add(map5);
49         list.add(map6);
50         list.add(map7);
51         System.out.println("原本的list" + list);
52 
53         //合并相同maid的map成为一个map
54         //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
55 
56         for (int i = 0; i < list.size(); i++) {
57             Map map = list.get(i);
58             // 从当前项的下一项开始检查
59             for (int j = i + 1; j < list.size(); j++) {
60                 Map<String, Object> childMap = list.get(j);
61                 // ID 相等
62                 if (null != map.get("maId") & null != childMap.get("maId")) {
63                     if (map.get("maId").equals(childMap.get("maId"))) {
64                         // 合并，此处需要先 remove
65                         list.remove(childMap);
66                         map.putAll(childMap);
67                     }
68                 }
69 
70             }
71         }
72         System.out.println("合并后的list:" + list);
73 
74 
75     }
76    
77 }

输出值：

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