Java Map 求交集 並集 差集

import com.google.common.collect.MapDifference;
import com.google.common.collect.Maps;

import java.util.Map;

public class MapUtil {

    /**
     * difference
     * Maps.difference(Map, Map)用來比較兩個Map以獲取所有不同點。該方法返回MapDifference對象
     */
    public static void u(Map<String,Object> map1, Map<String,Object> map2) {
        MapDifference<String, Object> difference = Maps.difference(map1, map2);
        // 是否有差異，返回boolean
        boolean areEqual = difference.areEqual();
        System.out.println("比較兩個Map是否有差異:" + areEqual);
        // 兩個map的交集
        Map<String, Object> entriesInCommon = difference.entriesInCommon();
        System.out.println("兩個map都有的部分（交集）===：" + entriesInCommon);
        // 鍵相同但是值不同值映射項。返回的Map的值類型為MapDifference.ValueDifference，以表示左右兩個不同的值
        Map<String, MapDifference.ValueDifference<Object>> entriesDiffering = difference.entriesDiffering();
        System.out.println("鍵相同但是值不同值映射項===：" + entriesDiffering);
        // 鍵只存在於左邊Map的映射項
        Map<String, Object> onlyOnLeft = difference.entriesOnlyOnLeft();
        System.out.println("鍵只存在於左邊Map的映射項:" + onlyOnLeft);
        // 鍵只存在於右邊Map的映射項
        Map<String, Object> entriesOnlyOnRight = difference.entriesOnlyOnRight();
        System.out.println("鍵只存在於右邊Map的映射項:" + entriesOnlyOnRight);
    }
}