java 登录时,要判断用户名、密码和验证码(随机四位字母和数字组成),同时正确才能登录成功
时间: 2024-05-02 08:21:36 浏览: 9
示例代码:
```
import java.util.Random;
import java.util.Scanner;
public class Login {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String username = "admin"; // 设置正确的用户名
String password = "123456"; // 设置正确的密码
String captcha = generateCaptcha(); // 生成随机验证码
System.out.println("验证码:" + captcha);
System.out.print("请输入用户名:");
String inputUsername = sc.nextLine();
System.out.print("请输入密码:");
String inputPassword = sc.nextLine();
System.out.print("请输入验证码:");
String inputCaptcha = sc.nextLine();
if (inputUsername.equals(username) && inputPassword.equals(password) && inputCaptcha.equalsIgnoreCase(captcha)) {
System.out.println("登录成功!");
} else {
System.out.println("登录失败!");
}
}
private static String generateCaptcha() {
Random random = new Random();
StringBuilder sb = new StringBuilder();
for (int i = 0; i < 4; i++) {
int type = random.nextInt(3); // 随机选择数字、大写字母或小写字母
switch (type) {
case 0:
sb.append((char) (random.nextInt(10) + '0')); // 数字
break;
case 1:
sb.append((char) (random.nextInt(26) + 'A')); // 大写字母
break;
case 2:
sb.append((char) (random.nextInt(26) + 'a')); // 小写字母
break;
default:
break;
}
}
return sb.toString();
}
}
```