随机验证码生成

 1 package com.Stringuse;
 2 
 3 import java.util.Random;
 4  //使用StringBuilder的方发创建验证码
 5 /*public class SuiJiMA {
 6     
 7     public static void main(String[] args) {
 8         
 9         StringBuilder   stringBuilder =  new StringBuilder();
10         Random  random = new Random();
11         for(int i=0; i<4;i++){
12             
13              int x = random.nextInt(10);
14             stringBuilder.append(x);    
15         }
16         System.out.print("验证码："+stringBuilder);
17     }
18 }*/
19 
20 //   使用空字符串
21 public class SuiJiMA {
22     public static void main(String[] args) {
23         String st = " ";
24         Random random = new Random();
25         for(int i=0;i<4;i++){
26             int x = random.nextInt(10);
27             st = st + x;
28         }
29         System.out.println("验证码："+st);
30     }
31 }

 1 //生成随机字母验证码
 2 public class SuiJiMA {
 3     public static void main(String[] args) {
 4       StringBuilder stringBuilder = new StringBuilder();
 5       Random random = new Random();
 6       for(int i=0;i<4;i++){
 7           int t = random.nextInt(2);
 8           char ch = t ==0? (char)(random.nextInt(26)+'a'):(char)(random.nextInt(26)+'A');
 9           stringBuilder.append(ch);
10       }
11       System.out.println(stringBuilder);
12     }
13 }