Java jFrame 登录屏幕，从 2 个文本文件中读取，在 netbeans 中

Question

所以我开始为我的PAT 12级任务创建这个项目，我遇到了一个减速带……我有一个登录屏幕，使用jFrame，在netbean中。我的问题是，我使用2个文本文件来存储数据：1个用于用户名，1个用于密码。它们使用扫描仪读取，并用#分隔。关键是，我使用同时循环验证用户名，但我无法验证与另一个文本文件中的用户名对应的密码。

所以你可以想象2个文本文件：

• 用户名
• 密码

当点击“登录”按钮时，它使用while循环来检查用户名是否已经存在。如果是，继续输入密码，否则“用户名不存在”。当在另一个文本文件的相同位置匹配密码时，问题就出现了。

如果有人能帮助我，这将是我的一周，拯救我的项目。请理解，Netbeans只允许您编辑特定区域的代码。我尽最大努力让我的代码干净易懂。

非常感谢，雪花吸血鬼

package Battlefield4;
import javax.swing.*;
import java.util.*;
import java.io.*;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Login extends javax.swing.JFrame
{

String Username;
String Password;

public Login()
{
    initComponents();
}
             //Can not edit from here on      
private void initComponents() {

    txtUsername = new javax.swing.JTextField();
    txtPassword = new javax.swing.JTextField();
    lblPassword = new javax.swing.JLabel();
    lblUsername = new javax.swing.JLabel();
    btnLogin = new javax.swing.JButton();
    btnCreate = new javax.swing.JButton();
    jLabel1 = new javax.swing.JLabel();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    setSize(new java.awt.Dimension(854, 480));
    getContentPane().setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());
    getContentPane().add(txtUsername, new org.netbeans.lib.awtextra.AbsoluteConstraints(320, 150, 210, -1));
    getContentPane().add(txtPassword, new org.netbeans.lib.awtextra.AbsoluteConstraints(320, 220, 210, -1));

    lblPassword.setText("Password");
    getContentPane().add(lblPassword, new org.netbeans.lib.awtextra.AbsoluteConstraints(320, 200, -1, -1));

    lblUsername.setText("Username");
    getContentPane().add(lblUsername, new org.netbeans.lib.awtextra.AbsoluteConstraints(320, 130, -1, -1));

    btnLogin.setText("Login");
    btnLogin.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            btnLoginActionPerformed(evt);
        }
    });
    getContentPane().add(btnLogin, new org.netbeans.lib.awtextra.AbsoluteConstraints(320, 290, -1, -1));

    btnCreate.setText("Create");
    btnCreate.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            btnCreateActionPerformed(evt);
        }
    });
    getContentPane().add(btnCreate, new org.netbeans.lib.awtextra.AbsoluteConstraints(460, 290, -1, -1));

    jLabel1.setIcon(new javax.swing.ImageIcon(getClass().getResource("/Battlefield4/Batfield/Background/Login (Small).jpg"))); // NOI18N
    jLabel1.setText("jLabel1");
    getContentPane().add(jLabel1, new org.netbeans.lib.awtextra.AbsoluteConstraints(0, 0, 860, 480));

    pack();
}                        
//Can not edit before this
private void btnLoginActionPerformed(java.awt.event.ActionEvent evt) {                                         
    //This is from where Netbeans lets you edit your code.
    try {
        File user = new File("C:\\Users\\John1012\\Documents\\NetBeansProjects\\PATProject\\src\\Battlefield4\\Batfield\\Users\\Username.txt"); //To create a universal file for Input & Output
        File pass = new File("C:\\Users\\John1012\\Documents\\NetBeansProjects\\PATProject\\src\\Battlefield4\\Batfield\\Users\\Password.txt"); //To create a universal file for Input & Output
        user.getParentFile().mkdirs(); //To denote the parent file
        pass.getParentFile().mkdirs(); //To denote the parent file
        Scanner scUser = new Scanner(user).useDelimiter("#"); //To scan the Username file
        Scanner scPass = new Scanner(pass).useDelimiter("#");
        Username = txtUsername.getText(); //This gets the user input
        Password = txtPassword.getText(); //This gets the user input
        int pos = 0; //Indicates the position of the Username in the save file

        while(scUser.hasNext())
        {
            pos = pos + 1;

            if(scUser.equals(Username))
            { //This is where it fails
                for (int i = 0; i <= 5; i++)
                {
                    while(scPass.hasNext())
                    {
                        System.out.print(scPass);
                    }
                }

                if(scPass.equals(Password))
                {
                    new Selection().setVisible(true);
                    this.dispose();
                }
                else
                {
                   JOptionPane.showMessageDialog(null,"Incorrect Password!");
                }
            }//This is where it works from. The above code is sketchy
            else
            {
                JOptionPane.showMessageDialog(null,"User Does Not Exist!");
            }
            scUser.close();
        }
    }
    catch (FileNotFoundException ex)
    {
        Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
    }
    catch (IOException ex)
    {
        Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
    }

}                                        

private void btnCreateActionPerformed(java.awt.event.ActionEvent evt) {                                          
   //Again this is from where Netbeans lets you edit
    try {
        File user = new File("C:\\Users\\John1012\\Documents\\NetBeansProjects\\PATProject\\src\\Battlefield4\\Batfield\\Users\\Username.txt"); //To create a universal file for Input & Output
        File pass = new File("C:\\Users\\John1012\\Documents\\NetBeansProjects\\PATProject\\src\\Battlefield4\\Batfield\\Users\\Password.txt"); //To create a universal file for Input & Output
        user.getParentFile().mkdirs(); //To denote the parent file
        pass.getParentFile().mkdirs(); //To denote the parent file
        Scanner scUser = new Scanner(user); //To scan the Username file
        Username = txtUsername.getText(); //This gets the user input
        Password = txtPassword.getText(); //This gets the user input

        if(scUser.nextLine().contains(Username)) //This reads the entire line and checks for an indexOf of those characters
        {
            JOptionPane.showMessageDialog(null,"User Already Exists!");
            scUser.close(); //Close the Scanner
        }
        else
        {
            scUser.close(); //Close the Scanner
            if("".equals(Password) || " ".equals(Password)) //Checks to see whether or not the user entered a password
            {
                JOptionPane.showMessageDialog(null,"Please Enter A Password!");
            }
            else
            {
               PrintWriter pwUser = new PrintWriter(new FileWriter(user,true)); //To Write to the Username file
               PrintWriter pwPass = new PrintWriter(new FileWriter(pass,true)); //To Write to the Password file
               pwUser.print(Username + "#");
               pwPass.print(Password + "#");
               pwUser.close();
               pwPass.close();

               new Selection().setVisible(true);
               this.dispose();
            }
        }
        scUser.close();
    }
    catch (FileNotFoundException ex)
    {
        Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
    }
    catch (IOException ex)
    {
        Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
    }

}                                         
 //Can no longer edit here
 public static void main(String args[]) {

    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(Login.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(Login.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(Login.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(Login.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }

    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new Login().setVisible(true);
        }
    });
}

// Variables declaration - do not modify                     
private javax.swing.JButton btnCreate;
private javax.swing.JButton btnLogin;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel lblPassword;
private javax.swing.JLabel lblUsername;
private javax.swing.JTextField txtPassword;
private javax.swing.JTextField txtUsername;
// End of variables declaration                   
}

Answer 1

所以我想出了怎么做。谢谢大家的帮助！

我把这个作为一个更简单的方法发布到@Tobi，希望能帮助那些不太先进或需要更简单帮助的人！

private void btnLoginActionPerformed(java.awt.event.ActionEvent evt) {                                         

    try {
        File user = new File("src\\Battlefield4\\Batfield\\Users\\Username.txt"); //To create a universal file for Input & Output
        File pass = new File("src\\Battlefield4\\Batfield\\Users\\Password.txt"); //To create a universal file for Input & Output
        user.getParentFile().mkdirs(); //To denote the parent file
        pass.getParentFile().mkdirs(); //To denote the parent file
        Scanner scUser = new Scanner(user).useDelimiter("#"); //To scan the Username file
        Scanner scPass = new Scanner(pass).useDelimiter("#"); //To scan the password file
        username = txtUsername.getText(); //This gets the user input
        password = txtPassword.getText(); //This gets the user input
        int pos = 0; //Indicates the position of the Username in the save file
        boolean loggedIn = false; //Flag to check if it's logged in

        while(scUser.hasNext() && scPass.hasNext()) //Runs files in congruency
        {
            if(scUser.next().equalsIgnoreCase(username) && scPass.next().equals(password))
            {
                loggedIn = true;
                scUser.close();
                scPass.close();
                new Selection(username).setVisible(true);
                this.dispose();
                break;
            }
        }
        scUser.close();
        scPass.close();
        if(loggedIn == false)
        {
            JOptionPane.showMessageDialog(null,"Incorrect Username or Password!");
        }

    }
    catch (FileNotFoundException ex)
    {
        Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
    }

}                                        

Answer 2

启动时映射所有用户，然后只检查地图。使用split来分隔用户名和密码。在调用onLoginCorrect()之前，请检查输入是否为空

private static final Logger LOG = LogManager.getLogger();
private final Map<String, String> users = new ConcurrentHashMap<>();

public Login() {
    super();
    final InputStream resource = this.getClass().getResourceAsStream("/users.txt");
    final Scanner scanner = new Scanner(resource);
    while (scanner.hasNext()) {
        final String input = scanner.nextLine();
        final String[] userPw = StringUtils.split(input, ':');
        this.users.put(userPw[0], userPw[1]);
    }
    scanner.close();
    IOUtils.closeQuietly(resource);
}

public boolean  isLoginCorrect(final String username,final String password) {
    final boolean result;
    if (StringUtils.equals(this.users.get(username), password)) {
        result = true;
    } else {
        Login.LOG.warn("No such user");
        result = false;
    }
    return result;
}