java Set去重

import java.util.*;

/**
 * @Author: ZhangHao
 * @Description: Set去重测试
 * @Date: 2020/4/2 16:30
 * @Version: 1.0
 */
public class SetTest {
    public static void main(String[] args) {
        Set<String> stringSet1 = new TreeSet<>();
        stringSet1.add("1");
        stringSet1.add("2");
        Set<String> stringSet2 = new TreeSet<>();
        stringSet2.add("2");
        stringSet2.add("3");
        stringSet1.addAll(stringSet2);
        System.out.println(stringSet1);

        SetTest setTest = new SetTest();
        People people1 = setTest.new People();
        People people2 = setTest.new People();
        People people3 = setTest.new People();
        Set<People> peopleSet1 = new HashSet<>();
        peopleSet1.add(people1);
        peopleSet1.add(people2);
        Set<People> peopleSet2 = new HashSet<>();
        peopleSet2.add(people2);
        peopleSet2.add(people3);
        peopleSet1.addAll(peopleSet2);
        System.out.println(peopleSet1);

        Map<People, Home> peopleHomeMap1 = new HashMap<>();
        Home home1= setTest.new Home();
        Home home2= setTest.new Home();
        Home home3= setTest.new Home();
        peopleHomeMap1.put(people1, home1);
        peopleHomeMap1.put(people2, home2);
        Map<People, Home> peopleHomeMap2 = new HashMap<>();
        peopleHomeMap2.put(people2, home2);
        peopleHomeMap2.put(people3, home3);
        Set<People> peopleSetFromMap1 = peopleHomeMap1.keySet();
        Set<People> peopleSetFromMap2 = peopleHomeMap2.keySet();
        // java.lang.UnsupportedOperationException
//        peopleSetFromMap1.addAll(peopleSetFromMap2);
        Set<People> peopleSet = new HashSet<>();
        peopleSet.addAll(peopleSetFromMap1);
        peopleSet.addAll(peopleSetFromMap2);
        System.out.println(peopleSet);
        System.out.println(peopleSet.iterator().next() == peopleSetFromMap1.iterator().next());
    }

    class People{
        public People(){
        }
    }

    class Home{
        public Home(){
        }
    }
}