Java Login Function

Question

Hey I need some help with my code.. I want it to say 'logged on' when the 'Pass' and 'getPass' is the same. and if its not its says 'logged off'.. but it says that all the time even if its correct. :/. Can Someone Help Me :(

p.s

sorry For My Bad English xd

package ca.sidez.main;

import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.border.EmptyBorder;

public class Main extends JFrame {
        private static final long serialVersionUID = 1L;

    private JPanel contentPane;
    private static JTextField txtName;
    private static JTextField txtPass;

    public static String Pass;
    public static String Pass2;
    public static String getPass;
    public static String getName;
    public static String File;

    public Main() {
        try {
    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (Exception e1) {
            e1.printStackTrace();
        }
    setResizable(false);
    setTitle("Login");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setSize(380, 380);
    setLocation(100, 100);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);

    txtName = new JTextField();
    txtName.setBounds(67, 50, 165, 28);
    contentPane.add(txtName);
    txtName.setColumns(10);

    txtPass = new JTextField();
    txtPass.setBounds(67, 100, 165, 28);
    contentPane.add(txtPass);
    txtPass.setColumns(20);

    JLabel lblName = new JLabel("Login");
    lblName.setBounds(127, 20, 100, 30);
    contentPane.add(lblName);


    JButton btnLogin = new JButton("Login");
    btnLogin.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            File = txtName.getText();
            Share();
        }
    });
    btnLogin.setBounds(60, 311, 117, 29);
    contentPane.add(btnLogin);

 }

public static void Share() {
    try {
//Checks if The Username Exists.
        File file = new File(File + ".txt");
        FileReader fileReader = new FileReader(file);
        BufferedReader bufferedReader = new BufferedReader(fileReader);
        StringBuffer stringBuffer = new StringBuffer();
        String line;
        while ((line = bufferedReader.readLine()) != null) {
            stringBuffer.append(line);
            stringBuffer.append("\n");
        }
        fileReader.close();
        Pass = stringBuffer.toString();
        getPass = txtPass.getText();
        getName = txtName.getText();
        System.out.println("Clients Password: " + getPass + " For Acc '" + getName + "' ");
        System.out.println("The Correct Password For Acc:  " + getName + " Is: " + Pass);
        if(Pass == getPass) {
            System.out.println("Logged In");
        } else {
            System.out.println("Logged Out");
        }
    } catch (IOException e) {
        System.out.println("Wrong Username Or Password");
    }
   }

public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                Main frame = new Main();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}
}

One day there will be a "spot the bug" olympics, it will have a string reference comparison and I will win the damn trophy for that. — Jeroen Vannevel
– Jeroen Vannevel, Commented Aug 1, 2014 at 19:59

user469104 · Accepted Answer · 2014-08-01 20:14:16Z

2

There are probably many issues with the code you have posted but one of them, and perhaps this is why it is not working as you think it should, is the adding of a newline to the stringbuffer:

     stringBuffer.append(line);
     stringBuffer.append("\n");

This would make the password in the file "mySecretPassword\n" which will not evaluate to true when compared to "mySecretPassword" using Equals (assuming that is the password in the file and what the user entered in the password field).

Your code would also not work if there is more than one line in the password file. If the assumption is that there will be only one line in the file and it is the password to verify against, then read only one line.

answered Aug 1, 2014 at 20:14

user469104

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1 Comment

Sidezpro Over a year ago

Yeah That Was The Problem. and yes i will only have one line in that text file :) thanks for the help

Aaron · Accepted Answer · 2014-08-01 20:19:16Z

1

if(Pass == getPass)

Should really be:

if(Pass.compareTo(getPass) == 0)

or

if(Pass.equals(getPass))

Are how you actually compare the content of the string.

if(Pass == getPass)

Is how you compare to see if they are both references to the same object.

Another Problem

while ((line = bufferedReader.readLine()) != null) {
    stringBuffer.append(line);
    stringBuffer.append("\n");
}
fileReader.close();
Pass = stringBuffer.toString();

Adds a new line to the end of Pass

You just want

while ((line = bufferedReader.readLine()) != null) {
    stringBuffer.append(line);
}
fileReader.close();
Pass = stringBuffer.toString();

edited Aug 1, 2014 at 20:19

answered Aug 1, 2014 at 20:02

Aaron

17110 bronze badges

11 Comments

Aaron Over a year ago

I think its because I tried to upvote my own answer so it gave me 3 down votes as punishment.

Kevin L Over a year ago

a few ideas: 1) he answered a poor question, 2) people protest to using .compareTo() == 0 instead of .equals() ?

Gumbo Over a year ago

@KevinL People who answer "poor questions" shuldn't get donvoted. People who ask questions that could be answered with one google search should be donvoted.

Mike Christensen Over a year ago

Meh I'm giving this answer a +1 until someone points out why it's so awful.

Kevin L Over a year ago

@Gumbo answering poor questions encourages the behavior of asking poor questions, see meta discussion meta.stackoverflow.com/a/255462/3666763 The community isn't completely in agreement on this, but as i said, those were ideas

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