Implementing A Servlet Application

I	ntroduction to Java Servlets

	Introduction
	Java Servlet is the one of the most important Java technologies. It is the simplest model to build a complete Java J2EE Web Application. Furthermore, even for complex J2EE Web Application that uses Struts, Spring, EJB and etc, they are still using Servlet for certain purposes such as Servlet Filter, Listener and etc. Thus, it is just a good idea for you to have well-built understanding of Java Servlet. Prior reading this tutorial, it would be excellent if you have mastered the basic Java programming languages. Servelet Example is give below with complete steps with screen-shots

Create a User Interface Using HTML

<html>: <head>; <title>; Find Employee Information; </title>; </head>; <body>; <form method="get" action="http://localhost:8080/emp_details">; <h2 align=center>Find Employee Information<center></h2>; <table>; <tr>; <th>Enter Employee Id>/th>; <td><input type=text name="id"></td>; </tr>; </table>; <input type=submit value=Submit>; </form>; </body>
</html>

Download Servlet.html

Servlet Coding

import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class EmployeeDetails extends HttpServlet{
    static int i;
    Connection con;
    PrintWriter out;
    ResultSet rs;
    public void init(){
       i=0;
       con=null;
       out=null;
       rs=null;
    }
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
       i++;
       out=response.getWriter();
       out.println("<b>You are user number " + i + "to visit this site</b><br><br>");
          try{
          Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
          con=DriverManager.getConnection("jdbc:odbc:EmployeesDB","sa","password");
          PreparedStatement pstmt=null;
          String query=null;
          query="select emp_fname,address,age,desig from Employee_Master where id=?";
          pstmt=con.prepareStatement(query);
          pstmt.setInt(1,Integer.parseInt(request.getParameter("id")));
          rs=pstmt.executeQuery();
          out.println("<b><center>Employee Details</center></b><br><br>");
          ResultSetMetaData rsmd=rs.getMetaData();
          int colcount=rsmd.getColumnCount();
          out.println("<table align=center border=1 cellpadding=2>");
          out.println("<tr>");
          for(int i=1; i<=colcount; i++){
             out.println("<th>" + rsmd.getColumnLabel(i) + "</th>");
             }
          out.println("<tr>");
          while(rs.next()){
             out.println("<tr>");
             out.println("<td>" + rs.getString("emp_fname") + "</td>");
             out.println("<td>" + rs.getString("address") + "</td>");
             out.println("<td>" + rs.getString("age") + "</td>");
             out.println("<td>" + rs.getString("desig") + "</td>");
             out.println("</tr>");
          }
          out.println("</table>");
          out.println("</body>");
          }
          catch(Exception e){
          out.println(e.toString());
          }
       }
       public void destroy(){
       try{
          i=0;
          con.close();
          out.close();
          rs.close();
       }
       catch(SQLException se){
          out.println(se.toString());
       }
    }
}

Download EmployeeDetails.java

Package the Servlet into a J2EE Application

Write a html file and name it as “Employee.html”
Write a java program and name it as “EmployeeDetails.java”
Set the path in the “command prompt”
set path=.;D:\progra~1\java\j2sdk1.5.0\bin;D:\Sun\AppServer\bin;
Set classpath=.;D:\progra~1\java\j2sdk1.5.0\lib;D:\Sun\AppServer\lib\j2ee.jar;
Now compile the “EmployeeDetails.java”
After the java programs are compiled successfully, you can close the command prompt.
Open the SQL Query Analyzer. In that
Create table Employee_Master(emp_fname varchar(20), address varchar(20), age int, desig varchar(20), id varchar(20));
Insert into Employee_Master values(‘Franklin’, ‘Pooteti’, 25, ‘MCA’, ‘1’);
Close the SQL Query Analyzer
Goto Control Panel (Start -> Settings ->Control Pannel)
Click Administrative Tools (in XP, click Performance and Maintenance) and then click Data Sources (ODBC)
Now

Click the "Add" button

Select “SQL Server” and click Finish

Write “EmployeesDB” in the Name textbox. Then in the Server textbox write “.”

Now Select the option “With SQL Server authentication using a login ID and password entered by the user”. Then select “Connect to SQL Server to obtain default settings for the additional configuration options”
Then in the Login ID write “sa” and then press Next button

Select the Change the default database to and give your database name (Optional)
Next click the Next button

Click the Finish button

Click Text Data Source button

Press OK button

Press OK button

Press OK button

Now goto Start -> Programs -> Sun Microsystems ->Application Server PE -> Start Default Server (wait till it start and then press any key)

Click Next To Continue...

About Author

Author Name           : Mr. R.Franklin Bourgia Singh
Country                    : INDIA
Working In               : Aryans Infoway (P) Ltd.
Email                        : admin@completetutorials.co.cc
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