import java.util.HashSet;

import java.util.Iterator;

public class Main {

    public static void main(String[] args) {

        HashSet set=new HashSet();

        set.add("a");

        set.add("b");

        set.add("c");

        set.add("d");

        set.add("e");

        Iterator ite=set.iterator();

        System.out.print("通过Iterator遍历HashSet: ");

        while(ite.hasNext()){

            System.out.print(ite.next()+" ");

        }

        System.out.println();

        System.out.print("HashSet的大小: ");

        System.out.println(set.size());

        System.out.print("HashSet是否包含元素1: ");

        System.out.println(set.contains(1));

        System.out.print("HashSet是否包含元素a: ");

        System.out.println(set.contains("a"));

        set.remove("b");

        String array[]=(String [])set.toArray(new String[0]);    //将HashSet变换为数组

        System.out.print("将元素b从set中移除后: ");

        for(String str:array){

            System.out.print(str);

        }

        System.out.println();

        HashSet otherset=new HashSet();

        otherset.add("a");

        otherset.add("c");

        otherset.add("e");

        HashSet removeset=(HashSet)set.clone();    //克隆

        removeset.removeAll(otherset);

        System.out.println(removeset);

        HashSet retainset=(HashSet)set.clone();

        retainset.retainAll(otherset);

        System.out.println(retainset);

    }

}

通过Iterator遍历HashSet: a b c d e

HashSet的大小: 5

HashSet是否包含元素1: false

HashSet是否包含元素a: true

将元素b从set中移除后: acde

[d]

[a, c, e]