java List中相同的数据合并到一起

谁借莪１个温暖的怀抱￠ 2024-03-26 08:04 30阅读 0赞

#### 文章目录 ####

*   *  代码
 *  总结

--------------------

### 代码 ###

List<Map<Object,Object>> mapList = new ArrayList<>();
            Map<Object,Object> map = new HashMap<>();
            map.put("C","111");
            map.put("NAME","LB");
            Map<Object,Object> map1 = new HashMap<>();
            map1.put("C","111");
            map1.put("NAME","LA");
            Map<Object,Object> map2 = new HashMap<>();
            map2.put("C","112");
            map2.put("NAME","LC");
            Map<Object,Object> map3 = new HashMap<>();
            map3.put("C","112");
            map3.put("NAME","Lh");
            Map<Object,Object> map4 = new HashMap<>();
            map4.put("C","113");
            map4.put("NAME","LC");
            Map<Object,Object> map5 = new HashMap<>();
            map5.put("C","114");
            map5.put("NAME","LF");
            mapList.add(map);
            mapList.add(map1);
            mapList.add(map2);
            mapList.add(map3);
            mapList.add(map4);
            mapList.add(map5);
    
            Map<Integer, List<Map<Object,Object>>> mapMap = new HashMap<>();
            for (Map<Object,Object> newMap : mapList){
        
                List<Map<Object, Object>>  newl = new ArrayList<>();
                // map是否包含此key，若已经包含则添加一个新的数字到对应value集合中
                if (mapMap.containsKey(Integer.valueOf(newMap.get("C").toString()))){
        
                    //mapList.add(Integer.valueOf(newMap.get("C").toString()),newMap);
                    mapMap.get(Integer.valueOf(newMap.get("C").toString())).add(newMap);
                }else{
        
                    newl.add(newMap);
                    mapMap.put(Integer.valueOf(newMap.get("C").toString()), newl);
                }
            }
            System.out.println(mapMap);

**运行结果**  
![在这里插入图片描述][8620df60c04a4c70bef6422e1dfd16b6.png]

--------------------

## 总结 ##

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[参考1][1]

[8620df60c04a4c70bef6422e1dfd16b6.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/26/b645f7625621417fbc134e7100b02ca3.png
[1]: https://www.cnblogs.com/invban/p/10318627.html?ivk_sa=1024320u