如何将用户和密码输入与文本文件进行比较？

Question

嘿！我正在使用Java中的Swing软件包创建一个简单的登录表单，并且在检查用户名和密码是否正确时遇到困难。

这是当前的代码：

public void actionPerformed(ActionEvent e) {
    try{
    File user = new File("Usernames.txt");
    File pass = new File("Passwords.txt");
    FileReader frUsername = new FileReader(user);
    FileReader frPassword = new FileReader(pass);
    BufferedReader brUsername = new BufferedReader(frUsername);
    BufferedReader brPassword = new BufferedReader(frPassword);
    String username = brUsername.readLine();
    String password = brPassword.readLine();

    if (e.getSource() == btnLogin){
        while(username != null && password != null){
           
        if ((txtUsername.getText()).equals(username) && (new String (jpfPassword.getPassword()).equals(password))){
            JOptionPane.showMessageDialog(null, "Welcome: " + username, "Login Successful",JOptionPane.INFORMATION_MESSAGE); //this is for testing purposes only
        }
        else{
            JOptionPane.showMessageDialog(null, "Invalid Username or Password", "Unable to Login",0); //this is for testing purposes only
        }
       
        break;
    }
    }
    brUsername.close();
    brPassword.close();
}
    catch(IOException err){
        System.err.println("File not found.");
    }
}

}

这个想法是在密码和用户名文件中存储多个帐户。例如，文件内容为：

username.txt：

       SampleUsername1
       SampleUsername2

password.txt：

    SamplePassword1
    SamplePassword2

如果从用户名文件中的第1行是“ sampleusername1”，则其密码也来自密码文件的第1行“ samplepassword1”。如果用户和密码在文件中不相同，则应给出“无效”错误。我知道将密码放入TXT文件并不安全，但这仅是出于实践目的，因为我仍在学习如何编码。任何类型的帮助和技巧都非常感谢。谢谢！

Answer 1

这对我来说很好：

public static void main(String[] args) {
    String txtUsername = "username2";
    String jpfPassword = "password2";
    try {
        File user = new File("Usernames.txt");
        File pass = new File("Passwords.txt");
        FileReader frUsername = new FileReader(user);
        FileReader frPassword = new FileReader(pass);
        BufferedReader brUsername = new BufferedReader(frUsername);
        BufferedReader brPassword = new BufferedReader(frPassword);
        String username = brUsername.readLine();
        String password = brPassword.readLine();

        boolean loginSuccess = false;
        while (username != null && password != null) {

            if ((txtUsername).equals(username) && (jpfPassword.equals(password))) {
                JOptionPane.showMessageDialog(null, "Welcome: " + username, "Login Successful", JOptionPane.INFORMATION_MESSAGE); //this is for testing purposes only
                loginSuccess = true;
                break;
            }
            username = brUsername.readLine();
            password = brPassword.readLine();
        }
        if (!loginSuccess) {
            JOptionPane.showMessageDialog(null, "Invalid Username or Password", "Unable to Login", 0); //this is for testing purposes only
        }
        brUsername.close();
        brPassword.close();

    } catch (IOException e) {
        e.printStackTrace();
    }
}

我的usernames.txt和passwords.txt看起来

username
username1
username2

分别

password
password1
password2

是这样的主要问题是您只检查第一行。将break;更改为readline（）方法后，并且每次检查名称时都不会给出失败的消息。这就是为什么您必须首先循环遍历所有内容，然后检查是否失败。