java:集合框架(产生10个1-20之间的随机数要求随机数不能重复)

import java.util.HashSet;
import java.util.Iterator;
import java.util.Random;

public class Tets1 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Random r=new Random();
		HashSet hs=new HashSet<>();
		while(hs.size()<10) {
			int num=r.nextInt(20)+1;
			hs.add(num);
		}
		Iterator it=hs.iterator();
		while(it.hasNext()) {
			System.out.println(it.next());
		}
		 
	}

}