Programming Technology (JAVA) Coding Solution

1. What is event handling in JAVA? Explain mouse event handling with suitable example code.

import javax.swing.*;
import java.awt.event.*;
public class MouseEventFile implements 
MouseListener,MouseMotionListener
{
    JTextField tf= new JTextField();
    public void runFrame()
    {
        JFrame frame= new JFrame("Mouse Events");
        frame.setSize(600,300);
        tf.setBounds(200,60,250,20);
        frame.add(tf);
        frame.setLayout(null);
        frame.setVisible(true);
        frame.addMouseListener(this);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
frame.setLocationRelativeTo(null);

}

    public void mouseClicked(MouseEvent mouseEvent) {
        tf.setText("you clicked");
    }
    public void mousePressed(MouseEvent mouseEvent) {

}

    public void mouseReleased(MouseEvent mouseEvent) {

}

 

    public void mouseEntered(MouseEvent mouseEvent) {
       tf.setText("In");

}

    public void mouseExited(MouseEvent mouseEvent) {
        tf.setText("Out");

}

    public void mouseDragged(MouseEvent mouseEvent) {

}

    public void mouseMoved(MouseEvent mouseEvent) {

}

    public static void main(String[] args) {
        MouseEventFile msf=new MouseEventFile();
        msf.runFrame();

} }

2. What is event delegation model? Explain button event handling with code example.

import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
/**
 * Created by ashoknath on 11/3/19.
 */
public class ButtonMet implements ActionListener {
    JFrame frame= new JFrame("Click Events");
    JTextField tf= new JTextField();
    JButton button1= new JButton("Print");
    JButton button2= new JButton("clear");
    public void runFrame()
    {
        frame.setSize(600,300);
        tf.setBounds(200,60,250,20);
        button1.setBounds(200, 150, 100, 40);
        button2.setBounds(400, 150, 100, 40);
        frame.add(tf);
        frame.add(button1);
        frame.add(button2);
        frame.setLayout(null);
        frame.setVisible(true);
        button1.addActionListener(this);
        button2.addActionListener(this);
        button1.setActionCommand("button1");
button1.setActionCommand("button2");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
frame.setLocationRelativeTo(null);
  }
        
public void actionPerformed(ActionEvent e)
  {
            String comm1= e.getActionCommand();
            if(comm1=="button1")
            {
                tf.setText("NCIT");
            }else{
                tf.setText(" ");

}

    
            if(comm1=="button2")
            {
                tf.setText("NCIT ");
            }else{
                tf.setText(" ");
            }

}

    public static void main(String[] args) {
        ButtonMet be= new ButtonMet();
        be.runFrame();

}

}

3. Write an event driven program in JAVA that closes the application on clicking the close button.

import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
/**
 * Created by ashoknath on 8/26/19.
 */
public class CloseButton implements ActionListener {
        JFrame frame= new JFrame("Background Changer");
JButton button1= new JButton("close");
        public void runFrame() {
            frame.setSize(600, 300);
            button1.setBounds(200, 150, 100, 40);
            frame.add(button1);
            frame.setLayout(null);
            frame.setVisible(true);
            button1.addActionListener(this);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
frame.setLocationRelativeTo(null);

}

        public void actionPerformed(ActionEvent e) {
            if(e.getSource()==button1) {
System.exit(0); 
}

}

        public static void main(String[] args) {
         CloseButton cb=new CloseButton();
            cb.runFrame();
        }
    }

4. Write an event driven program in JAVA that changes color to RED when clicking the

button change color on the application.

package background;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class BackgroundChanger implements ActionListener {
        JFrame frame= new JFrame("Background Changer");
    JButton button1= new JButton("Change Color");
    JButton button2= new JButton("close");
        public void runFrame() {
            frame.setSize(600, 300);
            button1.setBounds(200, 150, 100, 40);
            frame.add(button1);
            frame.add(button2);
            frame.setLayout(null);
frame.setVisible(true);
            button1.addActionListener(this);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
frame.setLocationRelativeTo(null);

}

    public void actionPerformed(ActionEvent e) {
        if(e.getSource()==button1)
        {
frame.getContentPane().setBackground(Color.red); }
else
{ 
frame.getContentPane().setBackground(Color.white);

}

}

        public static void main(String[] args) {
     BackgroundChanger bg= new BackgroundChanger();
            bg.runFrame();
        }

}

5. Write a swing program that will take input from two text boxes and one button when

clicked will show the words in uppercase in console

package com.ashok.swing.bank;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
/**
 * Created by ashoknath on 9/26/19.
 */

public class BoxTestConvert extends JFrame implements
ActionListener {
    JFrame frame= new JFrame("Click Events");
    JTextField textField= new JTextField();
    JTextField textField2= new JTextField();
    JButton button1= new JButton("Convert");
    public  BoxTestConvert()
{
frame.setSize(600,300); textField.setBounds(200,60,250,20); 
textField2.setBounds(200,100,250,20); 
button1.setBounds(200, 150, 100, 40); frame.add(textField);
frame.add(textField2);
frame.add(button1);
frame.setLayout(null);
frame.setVisible(true); button1.addActionListener(this); 
button1.setActionCommand("button1"); frame.setVisible(true); 
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
frame.setLocationRelativeTo(null);
    }
    public void actionPerformed(ActionEvent e) {
        String text1 = textField.getText();
        String text2 = textField2.getText();
        String comm1= e.getActionCommand();
        if(comm1=="button1")
   {
 textField.setText(text1.toUpperCase()); //If u write this code u will get the uppercase word in textbox
 textField2.setText(text2.toUpperCase()); //If u write this code u will get the uppercase word in textbox 
System.out.println(text1.toUpperCase()); // this will give u uppercase in console 
System.out.println(text2.toUpperCase()); // this will give u uppercase in console
       }else{
            textField.setText(" ");
        }

}

    public static void main(String[] args) {
        new BoxTestConvert();

} }

6. Write a program that will read character one by one from file. -File Handling

package handlefile;
 import java.io.*;
import java.util.Scanner;
/**
 * Created by ashoknath on 8/17/19.
 */
public class SimpleFile {
    public static void main(String[] args) {
Scanner scanner = new Scanner(System.in); 
try {
            FileInputStream fin = new
FileInputStream("File1.txt");
            FileOutputStream fout= new
FileOutputStream("File2.txt");
            int ch;
            while ((ch=fin.read())!= -1)
            {
                fout.write(ch);
}
System.out.println("File copying successful"); 
fin.close();
fout.close();

}catch(Exception ex){
System.err.print("The file cannot be created.");

} 

}

}

7. Java Servlet /Jsp A jsp file to input the details of student in jsp and process it

using servletProcessName.jsp

<%@ page language="java" contentType="text/html; 
charset=ISO-8859-1"pageEncoding="ISO-8859-1"%>
<!DOCTYPE html >
<html>
<head>
<body>
<h1>Registration Form</h1>
<form action="RegistrationController" method="post"> 
<table style="with: 50%">
<tr>

<td>Full Name</td>
<td><input type=”text” name=”fullname” /></

</tr> <tr>

<td>Address</td>
<td><input type=”text” name=”address” /></

</tr> <tr>

                   <td>Age</td>

<td><input type=”text” name=”age” /></td> </tr>

<tr>
<td>Qualification</td>
<td><input type=”text” name=”qual” /></td>

</tr> <tr>

<td>Percentage</td>
<td><input type=”text” name=”percent” /></

</tr> <tr>

                   <td>Year Passed</td>

<td><input type=”text” name=”yop” /></td> </tr>

</table>

<input type=”submit” value=”register” /> </form>

</body>
</html>

//displaying
display.jsp
<%@ page language=”java” contentType=”text/html; charset=ISO-8859-1″

pageEncoding=”ISO-8859-1″%>
<!DOCTYPE html >
<html>
<head>
<title>Display</title>
</head>
<body>
<% String name = request.getParameter(“fullname”);

<td>

<td>

<td>

    String Addr = request.getParameter("address");
    String age = request.getParameter("age");
    String Qual = request.getParameter("qual");
    String Persent = request.getParameter("percent");
    String Year = request.getParameter("yop"); %>

<table id =”nat”> <tr>

    <td>Full Name</td>
    <td><%= name %></td>
</tr>
<tr>
    <td>Address</td>
    <td><%= Addr %></td>

</tr> <tr>

    <td>Age</td>
    <td><%= age %></td>
</tr>
<tr>
    <td>Qualification</td>
    <td><%= Qual %></td>

</tr> <tr>

    <td>Percentage</td>
    <td><%= Persent %></td>
</tr>
<tr>
    <td>Year of Passout</td>
    <td><%= Year %></td>
</tr>
</table>
</body>
</html>
//registration controller servlet
registrationcontroller.java
package com.candidjava;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class RegistrationController extends HttpServlet {
    private static final long serialVersionUID = 1L; //ide
    protected void doPost(HttpServletRequest req,
HttpServletResponse res) throws ServletException, IOException
    {
        PrintWriter out = res.getWriter();
        String name = req.getParameter("fullname");
        String Addr = req.getParameter("address");
        String age = req.getParameter("age");
        String Qual = req.getParameter("qual");
        String Persent = req.getParameter("percent");
        String Year = req.getParameter("yop");
        if(name.isEmpty()||Addr.isEmpty()||age.isEmpty()||
Qual.isEmpty()||Persent.isEmpty()||Year.isEmpty())
        {
            RequestDispatcher rd =
req.getRequestDispatcher("processName.jsp");
out.println("<font color=red>Please fill all the
fields</font>");
 rd.include(req, res);
        }

else {

            RequestDispatcher rd =
req.getRequestDispatcher("Display.jsp");
            rd.forward(req, res);
        }

}

}

About the Author: Ashok Nath

Ashok Nath is an Author in Surajchand99.com.np and is pursuing Bachelor's Degree In Computer Engineering From Nepal College Of Information Technology (NCIT) Pokhara University Nepal.

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