同一个List<Map<String,Object>>集合中元素两两相比

List<Map<String, Object>> list = new ArrayList<>();
for(int j=0; j < 5; j++){
    Map<String, Object> map = new HashMap<>();
    for(int i=0; i <= 3; i++){
        map.put(CastUtil.castString(i),i);
    }
    list.add(map);
}

for(Map<String,Object> map : list){
    System.out.println(map);
}


for(int i=0; i < list.size()-1; i++){

        for(int j=list.size()-1; j > i; j--){
            Map<String, Object> zhengMap = list.get(i);
            Map<String, Object> fanMap = list.get(j);
            String zheng = zhengMap.get("0").toString();
            String fan = fanMap.get("0").toString();
            if(zheng.equals(fan) && fanMap.get("4") == null){
                for(Map.Entry<String,Object> entry:zhengMap.entrySet()){
                    if(!entry.getKey().equals("0")){
                        double value1 = CastUtil.castDouble(fanMap.get(entry.getKey()));
                        double value2 = CastUtil.castDouble(entry.getValue());
                        zhengMap.put(entry.getKey(),value1 + value2);
                        //标记字段表示已经比较过
                        fanMap.put("4",0);
                    }
                }
            }
        }
}

System.out.println();
System.out.println();
System.out.println();
for(Map<String,Object> map : list){
    System.out.println(map);
}

 

双层for循环为核心，采用正反向遍历，用标记字段标记已经比较过的元素