JAVA Set 交集，差集，并集

/**
 * Created by yuhui on 2017/7/11 0011.
 */
import java.util.HashSet;
import java.util.Set;

public class TestSet {

    public static void main(String[] args) {

        Set<String> result = new HashSet<String>();
        Set<String> set1 = new HashSet<String>() {
            {
                add("王者荣耀");
                add("英雄联盟");
                add("穿越火线");
                add("地下城与勇士");
            }   
        };

        Set<String> set2 = new HashSet<String>() {
            {
                add("王者荣耀");
                add("地下城与勇士");
                add("魔兽世界");
            }
        };

        result.clear();
        result.addAll(set1);
        result.retainAll(set2);
        System.out.println("交集：" + result);

        result.clear();
        result.addAll(set1);
        result.removeAll(set2);
        System.out.println("差集：" + result);

        result.clear();
        result.addAll(set1);
        result.addAll(set2);
        System.out.println("并集：" + result);

    }

}