utility

This article is an answer for my simple assignment i created several weeks ago for my friend, Zainul Iman. Its about creating a simple web application that can persist and retrieve values by putting it values on a java object and serialized it on a plain text file.

Okay, so basically i only create 4 files. Only 1 java files, 2 jsp and 1 servlet. And only adding several lines on web.xml file.
First is a simple java bean to store my inserted value,

package com.edw.bean;

import java.io.Serializable;

public class Student implements Serializable{    
    private String name;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }    
}

And a simple jsp file to serve as view layer, in here user can insert value which will be persist on java bean.

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Insert Value</title>
    </head>
    <body>
        <form method="post" action="StudentServlet">
        <table>
            <tr>
                <td>Insert Name : </td>
                <td><input type="text" name="name" /> </td>
            </tr>
            <tr>
                <td colspan="2"><input type="submit" /></td>                
            </tr>
        </table>
        </form>
    </body>
</html>

This is my servlet class, in this class i handle the serialization of the inserted value into java object

package com.edw.servlet;

import com.edw.bean.Student;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class StudentServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String name = request.getParameter("name");
        Student student = new Student();
        student.setName(name);
		
        FileOutputStream fileOutputStream2 = new FileOutputStream(new File("D:\\test12.txt"), false);
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(fileOutputStream2);
        objectOutputStream.writeObject(student);
        response.getWriter().println("Success....!!");
        response.getWriter().println("list of student ---> <a href=\"\">daftar.jsp</a>");
    }
}

And the serialized object will be read from “daftar.jsp” file,

<%@page import="com.edw.bean.Student"%>
<%@page import="java.io.ObjectInputStream"%>
<%@page import="java.io.File"%>
<%@page import="java.io.FileInputStream"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Daftar Nama</title>
    </head>
    <body>
        <h1>Registered Name is : </h1>
        <%
            try{
                FileInputStream fileInputStream = new FileInputStream(new File("D:\\test12.txt"));
                ObjectInputStream objectInputStream = new ObjectInputStream(fileInputStream);
                Student student = (Student)objectInputStream.readObject();
                out.print("<h1>"+student.getName()+"</h1>");
            }catch(Exception ex){                
                out.print(ex);
            }            
        %>
    </body>
</html>

Dont forget to register you servlet to web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <servlet>
        <servlet-name>StudentServlet</servlet-name>
        <servlet-class>com.edw.servlet.StudentServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>StudentServlet</servlet-name>
        <url-pattern>/StudentServlet</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>

Well it’s not too hard isnt it 😉