java - 用户在控制台输入密码时，显示星号(*)而不是纯文本

Question

I have tried the following codes both have different approaches.

Approach 1: It breaks when executing in the latest version of Eclipse IDE say 2020-03 whereas it works fine in Mars IDE.

This problem is already asked on this How to display asterisk for input in Java?.

方法一:

Package test;

import java.io.*;

public class Test {
    public static void main(final String[] args) {
        String password = PasswordField.readPassword("Enter password:");
        System.out.println("Password entered was:" + password);
    }
}

class PasswordField {

    public static String readPassword(String prompt) {
        EraserThread et = new EraserThread(prompt);
        Thread mask = new Thread(et);
        mask.start();

        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        String password = "";

        try {
            password = in.readLine();
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
        et.stopMasking();
        return password;
    }
}

class EraserThread implements Runnable {
    private boolean stop;

    public EraserThread(String prompt) {
        System.out.print(prompt);
    }

    @SuppressWarnings("static-access")
    public void run() {
        while (!stop) {
            System.out.print("\010*");

            try {
                Thread.sleep(1);
            } catch (InterruptedException ie) {
                ie.printStackTrace();
            }

        }
    }

    public void stopMasking() {
        this.stop = true;
    }
}

方法 2:

It does not work on Eclipse IDE but does work on the command line.

import java.io.Console;
public class Main {

    public void passwordExample() {        
        Console console = System.console();
        if (console == null) {
            System.out.println("Couldn't get Console instance");
            System.exit(0);
        }

        console.printf("Testing password%n");
        char[] passwordArray = console.readPassword("Enter your secret password: ");
        console.printf("Password entered was: %s%n", new String(passwordArray));

    }

    public static void main(String[] args) {
        new Main().passwordExample();
    }
}

Answer 1

方法 1 的程序不起作用，因为橡皮擦线程似乎未关闭。您应该将 stopMasking 上的初始 boolean 值更改为 false，然后在 catch 后告诉将其设置为 true。有许多可用的资源和代码可以完全做到这一点。我找到的最好的一个在这里:

http://www.cse.chalmers.se/edu/year/2018/course/TDA602/Eraserlab/pwdmasking.html

它在我的 Eclipse 2020 版本中运行。就您的第二种方法而言，控制台不适用于 IDE 中的用户输入，因此存在问题，但命令行中没有问题。如果你想使用这个版本，你可以用扫描仪替换控制台:

 import java.util.Scanner

 Scanner input = new Scanner(System.in);
 String password = input.nextLine();
 //implementation

我还建议导入您需要的特定类文件。导入所有 java.io 将使您的程序陷入困境。希望有帮助!