Question

我正在编写用于学习目的的短代码，要求用户输入密码以登录Facebook。我正在测试异常处理，由于某种原因，密码错误时 Catch 部分未执行。代码是：

import java.util.Scanner;

public class FacebookLogin {


    public static void printPassword() {
        Scanner sc = new Scanner(System.in);
        String password;

        try {

            System.out.print("Enter your password : ");
            password = sc.next();

        } catch (Exception x) {
            do {            
            System.out.println("Your password is incorrect. Try again!");
            System.out.print("Enter your password : ");
            sc.nextLine();
            password = sc.next();


            } while (password != "password");
        }
        sc.close();

    }

    public static void main(String[] args) {


        System.out.println("Welcome to Facebook!");

        printPassword();

        System.out.println("Congratulations, you have logged in to Facebook!");


    }

}

上面的脚本很少运行：

欢迎使用Facebook！

输入密码：ksskasjaks

恭喜，您已登录Facebook！

另一次跑步：

欢迎使用Facebook！

输入您的密码：密码

恭喜，您已登录Facebook！

我例外，例如，这里唯一的密码是“密码”：

欢迎使用Facebook！

输入密码：ksskasjaks

您的密码不正确。再试一次！

输入您的密码：密码

恭喜，您已登录Facebook！

任何线索为什么它没有按预期运行？谢谢。

Answer 1

尝试捕获：

 public static void enterPassword() throws Exception {
    Scanner sc = new Scanner(System.in);
    String password;
    System.out.print("Enter your password : ");
    password = sc.next();
    if (!password.equals("password")) {
        throw new Exception();
    }
}

public static void printPassword() {
    try {
        enterPassword();
    } catch (Exception e) {
        System.out.println("Your password is incorrect. Try again!");
        printPassword();
    }
}

public static void main(String[] args) {


    System.out.println("Welcome to Facebook!");

    printPassword();

    System.out.println("Congratulations, you have logged in to Facebook!");


}

Answer 2

不需要尝试捕获，我想这就是您想要的：

public static void printPassword() {
    Scanner sc = new Scanner(System.in);
    String password;

    System.out.print("Enter your password : ");
    sc.nextLine();
    password = sc.next();
    while (!password.equals("password")) {
        System.out.println("Your password is incorrect. Try again!");
        System.out.print("Enter your password : ");
        sc.nextLine();
        password = sc.next();
    }

    sc.close();

}

public static void main(String[] args) {


    System.out.println("Welcome to Facebook!");

    printPassword();

    System.out.println("Congratulations, you have logged in to Facebook!");


}

捕获部分Try-Catch没有执行

2 个答案: