List<Map<String, Object>> 去出重复

List<Map<String, Object>> 去出重复

public static void main(String[] args) {
    String [] array= {"name","age"};
    List<Map<String, Object>> oldList = getTestData();
    getListMap(oldList,"name",array);
    getListMap(oldList,"name");
    System.out.println(getListMap(oldList,"name",array));

}

public static List<Map<String, Object>> getTestData() {
    List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
    Map<String, Object> map = new HashMap<String, Object>();
    map.put("name", "A");
    map.put("age", "0");
    map.put("age1", "0");
    Map<String, Object> map1 = new HashMap<String, Object>();
    map1.put("name", "B");
    map1.put("age", "1");
    map.put("age1", "0");
    Map<String, Object> map2 = new HashMap<String, Object>();
    map2.put("name", "A");
    map2.put("age", "1");
    map.put("age1", "1");
    list.add(map);
    list.add(map1);
    list.add(map2);
    return list;
}

1.去出重复的key

/**
 *  List<Map<String, Object>>  去出重复的key
 * @param str Map<String, Object> 中对比的key
 * @return
 */
public static List<Map<String, Object>> getListMap(List<Map<String, Object>> oldList,String str) {

    List<Map<String, Object>> newList = new ArrayList<Map<String, Object>>();
    for (int i = 0; i < oldList.size(); i++) {
        Map<String, Object> oldMap = oldList.get(i);
        if (newList.size() > 0) {
            boolean isContain = false;
            for (int j = 0; j < newList.size(); j++) {
                Map<String, Object> newMap = newList.get(j);
                if (newMap.get(str).equals(oldMap.get(str))) {
                    for (String key : oldMap.keySet()) {
                        newMap.put(key, oldMap.get(key));
                    }
                    isContain = true;
                    break;
                }
            }

            if (!isContain) {
                newList.add(oldMap);
            }

        } else {
            newList.add(oldMap);
        }
    }
    return newList;
}

2.去出重复的key,保留这定的key

/**
 *  List<Map<String, Object>>   去出重复的key,保留这定的key
 * @param str Map<String, Object> 中对比的key
 * @param array 需要保留的key
 * @return
 */
public static List<Map<String, Object>> getListMap(List<Map<String, Object>> oldList,String str,String [] array) {

    List<Map<String, Object>> newList = new ArrayList<Map<String, Object>>();
    for (int i = 0; i < oldList.size(); i++) {
        Map<String, Object> oldMap = oldList.get(i);
        Map<String, Object> oldMap1 = new HashMap<String, Object>();

        for (String  arr : array) {
            oldMap1.put(arr, oldMap.get(arr));
        }
        if (newList.size() > 0) {
            boolean isContain = false;
            for (int j = 0; j < newList.size(); j++) {
                Map<String, Object> newMap = newList.get(j);
                if (newMap.get(str).equals(oldMap.get(str))) {
                    isContain = true;
                    break;
                }
            }
            if (!isContain) {
                newList.add(oldMap1);
            }
        } else {
            newList.add(oldMap1);
        }
    }
    return newList;
}

标签：Map,get,重复,newList,List,key,put
来源： https://www.cnblogs.com/yuangyuan/p/16449547.html