數字加字母

public class RandomTest { 
public static void main(String[] args) { 
 String[] beforeShuffle = new String[] { "2", "3", "4", "5", "6", "7",  
"8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J",  
"K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V",  
"W", "X", "Y", "Z" };  
     List list = Arrays.asList(beforeShuffle);  
     Collections.shuffle(list);  
     StringBuilder sb = new
 
 StringBuilder();  
     for (int i = 0; i < list.size(); i++) {  
         sb.append(list.get(i));  
     }  
     String afterShuffle = sb.toString();  
     String result = afterShuffle.substring(5, 9);  
    System.out .print(result) ;
}}

隨機生成六位數字

public static String getSix(){
    Random rad=new 
 
Random();

    String result  = rad.nextInt(1000000) +"";

    if(result.length()!=6){
        return getSix();
    }
    return result;
}