LearnJava

Wednesday, 15 April 2015

How to populate Drop Down From Database Table in Java

Before create project you have to understand from a JSP file you have to create JDBC Connection with default port 3306 and call HTML Code inside JSP page :--

==========================index.jsp====================================

<%@ page import="java.sql.*" %>
<%ResultSet resultset =null;%>

<HTML>
<HEAD>
<TITLE>Welcome in Java by Anand,Bangalore</TITLE>
</HEAD>

<BODY BGCOLOR=#66CCFF>

<%
Connection con = null;
try {
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/Anand";
con = DriverManager.getConnection(url, "root", "pass@123");
Statement statement = con.createStatement() ;
resultset =statement.executeQuery("select * from blore") ;
%>

<center>
<h1> Welcome in Java by Anand,Bangalore</h1>
<select>
<% while(resultset.next()){ %>
<option><%= resultset.getString(2)%></option>
<% } %>
</select>
</center>

<%

}
catch(Exception e)
{
out.println("wrong entry"+e);
}
%>

</BODY>
</HTML>

======================Create Table Form DB=========================

> Create Database Anand;
> use Anand;
> Create table blore(id int(4), city varchar(30));;
> insert into blore values('1',"Rewa");
insert into blore values('2',"Pune");
insert into blore values('3',"Bangalore");
insert into blore values('4',"Satna");

Monday, 13 April 2015

Simple Login Form With Servlet Forwarding

For Creating a login form with Servlet we have require some files
For fornt End:-index.html
For Forwarding control: Demo.java (Create as a servlet not a normal java file)
-----
index.html
---
<!DOCTYPE html>

<html><body>

        <form action="welcome" method="get" align="center">

                    Enter your name<input type="text" name="name"> <br>


                    Enter you password<input type="password" name="password"> <br>

            <input type="submit" value="login">
        </form>
</html>

============= Demo.java================

import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/

/**
*
* @author ananddw
*/

public class Demo extends HttpServlet{

public void doGet(HttpServletRequest req,HttpServletResponse res)throws ServletException,IOException
{

res.setContentType("text/html");

PrintWriter pw=res.getWriter();

String name=req.getParameter("name");
    System.out.println("Name is "+name);

String password=req.getParameter("password");
    System.out.println("Password is "+password);

pw.println("Welcome :-"+name +",with password:-"+password);

}
}
===============web.xml=======================
<web-app>

<servlet>
<servlet-name>anand</servlet-name>
<servlet-class>Demo</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>anand</servlet-name>
<url-pattern>/welcome</url-pattern>
</servlet-mapping>

</web-app>
============================================
Run this programme on server make sure that while creating a project you create dynamic web project else you will get Error .

Wednesday, 8 April 2015

Basic HTML Tag Used



<html>
<head>
<title> Welcome in the World of HTML </title>

<form align="center">

<body bgcolor="##33CCFF">

<select name="DropDown">

<option id="1" value="Anand" > Anand </option>

<option id="2" value="Antrish" >Antrish </option>

<option id="3" value="Ajeet" >Ajeet </option>

</select>

<br></br>

DatePicker: <input type="date" value="date"/>

<br></br>

Name:<input type="text" name="Username" />

<br></br>

Password:<input type="password" name="password" />

<br></br>

Male:<input type="radio" name="Male" value="male" checked="checked" />

Female:<input type="radio" name="Male" value="male" checked="checked" />

<br></br>

ON:<input type="checkbox" name="ON" value="ON" checked="checked" />

OFF:<input type="checkbox" name="OFF" value="OFF" checked="checked" />

<br></br>

<ol>

<li>Ajeet</li>

<li>Antrish</li>

<li>Anand</li>

</ol>


<br></br>
<input type="file" name="Browse File" value="" width="50" />

<br></br>

<a href="http://learnjavabyanand.blogspot.in/">Click here</a>

<br></br>

<input type="submit" value="Submit" name="Submit" />

</bdoy>

</form>

</head>

</html>

Tuesday, 7 April 2015

How to get client IP address in a servlet

package com.anand;

import java.io.IOException;
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 ClientIP extends HttpServlet {

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

response.setContentType("text/html");
PrintWriter out = response.getWriter();
String name = request.getParameter("name");
System.out.println("Eneter Name : " + name);
System.out.println("IP Address of request : </font></b>" +
request.getRemoteAddr()+"<h3>");

}
}

How to Get Client IP Address Using Java Code

/*
* @author :Anand
*/

package com.anand;

import java.net.InetAddress;
import java.net.UnknownHostException;

public class IP{

public static void main(String[] args) {

InetAddress ip;
try {

ip = InetAddress.getLocalHost();
System.out.println("Your IP is====>" + ip.getHostAddress());

} catch (UnknownHostException e) {
System.out.println("catch the exception if Error Come ===>"+e);

e.printStackTrace();

}

}

}

Saturday, 4 April 2015

"How to Read file Line by line from your system Using java code "

package com.Anand;

/*
* Created by : Anand
* Date: 04-APR-2015
* */

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class Reader {

public static void main(String[] args) {

try (
BufferedReader br = new BufferedReader(new FileReader("E:\\Anand.txt")))

{
System.out.println("Read file ok ===> "+br);
String LinebyLine;

while ((LinebyLine = br.readLine()) != null) {
System.out.println("Read file Line by line===> "+LinebyLine);
}

} catch (IOException e) {
e.printStackTrace();
}

}}

Wednesday, 1 April 2015

======================================================================
How to See Total Visitors in webpage Using HTMl front End and Servlet Used for forwarding the Control ?
=======================================================================
For creating this project we need to create Some files like :-
index.jsp :- for front page
logout.jsp:- for log out page

________________________________index.jsp________________________________________

<html>
<body bgcolor="#FFCCFF">
<h1 align="center">Welcome to the World of java </h1>
<table align="right">
<tr>
<td>
<h4>
Total Visited :<%=application.getAttribute("TV") %>
</h4></td>
</tr>
<tr>
<td>
<h4>
Total Active :<%=application.getAttribute("TA") %>
</h4></td>
</tr>
</table>
<br />
<br />
<h4 align="center">Home page</h4>
<br />
<br />
<a href="logout.jlc">LOGOUT</a>
</body>
</html>

____________________________________Logout.jsp____________________________________
<%@ page session="false"%>
<html>
<body bgcolor="#FFCCFF">
<h1>Welcome to the World of java </h1>
<table align="right">
<tr>
<td>
<h4>
Total Visited :<%=application.getAttribute("TV") %>
</h4></td>
</tr>
<tr>
<td>
<h1>
Total Active :<%=application.getAttribute("TA") %>
</h1></td>
</tr>
</table>
<br />
<br />
<h4>You have logged out successfully</h4>
<br />
<br />
<a href="index.jsp">Go To Index Page</a>
</body>
</html>

======================================================================
Now for forwarding a Control we have create three servlet classes
LogoutServlet.java
MyContextListener.java
MySessionListener.java

______________________________LogoutServlet.java ________________________________
package com.servlet;

import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class LogoutServlet extends HttpServlet {
protected void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
HttpSession sess=req.getSession(false);
if(sess!=null)
sess.invalidate();
RequestDispatcher rd=req.getRequestDispatcher("logout.jsp");
rd.forward(req, res);
}

}

__________________________MyContextListener.java________________________________

package com.servlet;

import javax.servlet.ServletContext;

import javax.servlet.ServletContextEvent;

import javax.servlet.ServletContextListener;

public class MyContextListener implements ServletContextListener {

public void contextInitialized(ServletContextEvent event) {

System.out.println("**ContextInitialized***");

ServletContext ctx=event.getServletContext();

ctx.setAttribute("TV", 0);

ctx.setAttribute("TA", 0);

}

public void contextDestroyed(ServletContextEvent arg0) {

System.out.println("***contextDestroyed**");

}

__________________________MySessionListener.java______________________________

package com.servlet;

import javax.servlet.ServletContext;

import javax.servlet.http.HttpSession;

import javax.servlet.http.HttpSessionEvent;

import javax.servlet.http.HttpSessionListener;

public class MySessionListener implements HttpSessionListener {

public void sessionCreated(HttpSessionEvent event) {

HttpSession sess=event.getSession();

ServletContext ctx=sess.getServletContext();

int tv=(Integer) ctx.getAttribute("TV");

tv++;

ctx.setAttribute("TV", tv);

int ta=(Integer) ctx.getAttribute("TA");

ta++;

ctx.setAttribute("TA", ta);

}

public void sessionDestroyed(HttpSessionEvent event) {

HttpSession sess=event.getSession();

ServletContext ctx=sess.getServletContext();

int ta=(Integer) ctx.getAttribute("TA");

ta--;

ctx.setAttribute("TA",ta);

}

====================================================================

For mapping

web.xml

_______________________________web.xml___________________________________

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">

<display-name>Lab29</display-name>

<welcome-file-list>

<welcome-file>index.jsp</welcome-file>

</welcome-file-list>

<servlet>

<servlet-name>logoutServ</servlet-name>

<servlet-class>com.servlet.LogoutServlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>logoutServ</servlet-name>

<url-pattern>/logout.jlc</url-pattern>

</servlet-mapping>

<listener>

<listener-class>com.servlet.MyContextListener</listener-class>

</listener>

<listener>

<listener-class>com.servlet.MySessionListener</listener-class>

</listener>

</web-app>

==================================================================

Please find attached image where we put all these files so it can be accessible and O/P Console as well .

if any Doubt and suggestion wanted Contact any time

Thanks & Regards

Anand Dwivedi

Software Developer

Email: ananddwivedi92@gmail.com