public class Test {
  	public static void main(String[] args){
  	    Random ran = new Random(); 	    Set 
    
      set = new HashSet
     
      (); 	    while(set.size()==10?false:true){
  	    	int num = ran.nextInt(20)+1; 	    	set.add(num); 	    } 	    Iterator
      
        it = set.iterator(); 	    int count = 0; 	    while(it.hasNext()){
  	    	System.out.println("第"+ ++count +"个随机数 =="+it.next()); 	    } 	} }