Login Form Java

In Java, a form for entering authentication credentials to access the restricted page is referred to as a Login form. A login form contains only two fields, i.e., username and password. Each user should have a unique username that can be an email, phone number, or any custom username.

After submitting the login form, the underlying code of the form checks whether the credentials are authentic or not to allow the user to access the restricted page. If the users provide unauthentic credentials, they will not be able to forward the login form.

In Java, we can develop the login form by using Swing technology. We implement the LoginFormDemo.java class in which we create two text fields, i.e., text1 and text2, for setting the username and password. We also create a button for performing the action.

Steps to create login form:

In order to create a login form in Java, we have to follow the following steps:

Create a class that uses the JFrame and ActionListener to design the login form and perform the action.
Create user interface components using swings and awt and add them to the panel.
Override the actionPerformed() method that will call on the button click.
In this method, we will verify the user entered credentials.
Create a new page using JFrame and navigate the user to it if the credentials are authentic.
Else show an error message to the user.

Let's follow the above steps and implement the login form using swing and awt in Java:

LoginFormDemo.java

//import required classes and packages
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.lang.Exception;

//create CreateLoginForm class to create login form
//class extends JFrame to create a window where our component add
//class implements ActionListener to perform an action on button click
class CreateLoginForm extends JFrame implements ActionListener
{
	//initialize button, panel, label, and text field
	JButton b1;
	JPanel newPanel;
	JLabel userLabel, passLabel;
	final JTextField  textField1, textField2;
	
	//calling constructor
	CreateLoginForm()
	{	
		
		//create label for username 
		userLabel = new JLabel();
		userLabel.setText("Username");		//set label value for textField1
		
		//create text field to get username from the user
		textField1 = new JTextField(15);	//set length of the text

		//create label for password
		passLabel = new JLabel();
		passLabel.setText("Password");		//set label value for textField2
		
		//create text field to get password from the user
		textField2 = new JPasswordField(15);	//set length for the password
		
		//create submit button
		b1 = new JButton("SUBMIT");	//set label to button
		
		//create panel to put form elements
		newPanel = new JPanel(new GridLayout(3, 1));
		newPanel.add(userLabel);	//set username label to panel
		newPanel.add(textField1);	//set text field to panel
		newPanel.add(passLabel);	//set password label to panel
		newPanel.add(textField2);	//set text field to panel
		newPanel.add(b1);			//set button to panel
		
		//set border to panel 
		add(newPanel, BorderLayout.CENTER);
		
		//perform action on button click 
		b1.addActionListener(this);		//add action listener to button
		setTitle("LOGIN FORM");			//set title to the login form
	}
	
	//define abstract method actionPerformed() which will be called on button click 
	public void actionPerformed(ActionEvent ae)		//pass action listener as a parameter
	{
		String userValue = textField1.getText();		//get user entered username from the textField1
		String passValue = textField2.getText();		//get user entered pasword from the textField2
		
		//check whether the credentials are authentic or not
		if (userValue.equals("test1@gmail.com") && passValue.equals("test")) {	//if authentic, navigate user to a new page
			
			//create instance of the NewPage
			NewPage page = new NewPage();
			
			//make page visible to the user
			page.setVisible(true);
			
			//create a welcome label and set it to the new page
			JLabel wel_label = new JLabel("Welcome: "+userValue);
			page.getContentPane().add(wel_label);
		}
		else{
			//show error message
			System.out.println("Please enter valid username and password");
		}
	}
}
//create the main class
class LoginFormDemo
{
	//main() method start
	public static void main(String arg[])
	{
		try
		{
			//create instance of the CreateLoginForm
			CreateLoginForm form = new CreateLoginForm();
			form.setSize(300,100);	//set size of the frame
			form.setVisible(true);	//make form visible to the user
		}
		catch(Exception e)
		{	
			//handle exception 
			JOptionPane.showMessageDialog(null, e.getMessage());
		}
	}
}

NewPage.java

//import required classes and packages
import javax.swing.*;
import java.awt.*;

//create NewPage class to create a new page on which user will navigate
class NewPage extends JFrame
{
	//constructor
	NewPage()
	{
		setDefaultCloseOperation(javax.swing.
		WindowConstants.DISPOSE_ON_CLOSE);
		setTitle("Welcome");
		setSize(400, 200);
	}
}

Output:

Now, when we run the LoginFormDemo.java class, a panel will be open having the label, text fields, and button. We enter the credentials and hit on the submit button. If the credentials are authentic, the login form will navigate us to the welcome page as described below: