12.9

import java.awt.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.LineBorder;
 
public class Test extends JFrame
{
     
    public static void main(String[] args) {
         
        LineBorder lb = new LineBorder(Color.black,2);
        Test t1 = new Test();
        t1.setSize(320,200);
        t1.setLayout(new GridLayout(1,3));
        
        int[] a = random(3,54);
        
        for(int i=0;i<3;i++){
        t1.add(new JLabel(new ImageIcon("card/"+a[i]+".png")));}        
        
        t1.setDefaultCloseOperation(EXIT_ON_CLOSE);
        t1.setLocationRelativeTo(null);
        t1.setVisible(true);        
    }
    
    
    public static int[] random(int number,int max){
        //从max中产生number个随机数
        //output number from max value
        int[] array1 = new int[number];
//        int[] array2 = new int[max];
        array1[0] = (int)Math.round(Math.random()*max)+1;
        
        for(int i = 1; i < number; i++){  
            array1[i] = (int)Math.round(Math.random()*max)+1;
                for(int j =0; j<i; j++){
                    
                while(array1[i] == array1[j]){
                array1[i] = (int)Math.round(Math.random()*max)+1;
                }
                
                }
        }
        return array1;
    }
    
}