生成验证码

 1 //生成四位的验证码
 2         
 3         
 4         //利用split截取
 5         
 6         String str = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
 7         
 8         String []str1 = str.split("");//分割字符串，并生成数组
 9         
10 //        for(String x:str1){
11 //            
12 //            System.out.println(x);
13 //        }
14         String Code = "";//声明一个空的字符串
15         
16         Random ran = new Random();
17         
18         for(int i = 0;i<4;i++){
19             
20             int j = ran.nextInt(62);
21             
22             if(j == 0){                    //去除split分割出来的那个空的char
23                 
24                 Code = Code + str1[j+1];
25             }
26             else{
27                 
28                 Code = Code + str1[j];
29             }
30         }
31         System.out.println("生成的验证码1是："+Code);
32         
33         
34         //利用subSting来分割
35         
36         str = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
37         
38         Random ran1 = new Random();
39         
40         System.out.print("生成的验证码2是：");
41         
42         for(int a = 0;a<4;a++){            //循环四次截取四个字符串
43             
44             int i = ran1.nextInt(str.length()-1);
45             
46             System.out.print(str.substring(i,i+1));
47         }
48         System.out.println();
49         
50