生成指定位数的随机验证码
生成指定数目的验证码,可能含有大小写字母或者数字
大写字母AZ的ASCII码值从6590,小写字母az的ASCII码值从97122
import java.util.Random;
import java.util.Scanner;
//生成指定数目的验证码,可能含有大小写字母或者数字
public class Practice3 {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("请输入你想要生成的验证码的位数:");
int num = scanner.nextInt();
Random random = new Random();
//这里是重点
for (int i = 0; i < num; i++) {
String code = ""; //定义一个字符串接收随机产生的
int type = random.nextInt(3);
switch (type) {
case 0: {
char a = (char) (random.nextInt(26) + 65);
code += a;
break;
}
case 1: {
int b = random.nextInt(10);
code += b;
break;
}
case 2: {
char c = (char) (random.nextInt(26) + 97);
code += c;
break;
}
}
System.out.print(code);
}
}
}