Wednesday, July 4, 2012

how to deploy a servlet application in tomcat

Step to Deploy servlet application on tomcat web-server:

Step-1  Installing Tomcat :
If you have tomcat server already installed on your system go to step-2 directly.
Otherwise download the tomcat setup or zip file from and extract the files wherever you prefer.Extracting is enough in case of zip file download,no special installation setup is required.

Step-2 Setting environment variables
 >> Set JAVA_HOME variable to your JDK installation directory i.e C:\Program Files\Java\jdk1.6.0 in my
      System.It may be different on your system so check for it.
>> Set classpath for servlet-api.jar file which contains all the servlet libraries which is essential for compiling
      any servlet application.This servlet-api.jar file is provided with your server product in a location similar to
      "D:\apache-tomcat-6.0.29\lib\servlet-api.jar" ,this path may vary according to the installation location of 
       tomcat server.
       you need to execute this command from command prompt to set classpath:
       set classpath=D:\apache-tomcat-6.0.29\lib\servlet-api.jar;
       and your classpath is set proceed to next step.

Step-3 Designing Basic components like a servlet,html page.

>> Create a simple html file which will be used to invoke the servlet class.


<form action="./myServlet" method="get">
<input type="submit"/>

>> Now its time to create a servlet class.


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

public class Myservlet extends HttpServlet
     public void doGet(HttpServletRequest req,HttpServletResponse resp)throws ServletException,IOException
          PrintWriter pw=resp.getWriter();
          pw.println("<html><center>this is servlet response</center></html>");


Step-4 Compile the servlet class.

Open the command prompt
Change current directory to the one which contains your file
Now execute command:   "javac" 
It will generate the class file for your servlet if there is no error.

Step-5 Create a deployment descriptor file i.e web.xml
deployment descriptor contains the servlet information like servlet class,servlet mapping and url pattern for which the container will invoke the servlet.



Step-6 Arranging all the above components in a standard directory structure

Create a root folder for your application i.e Sample here in my example
Inside root folder create a new folder WEB-INF.
Inside WEB-INF create sub-folder classes and arreange the all the files as shown in the directory structure.
Your final directory structure should look like the below one.

Step-7 Deploy the Application 

Deployment is nothing but placing root folder of your application inside the
"D:\apache-tomcat-6.0.29\webapps "    folder  that is inside the server installation directory.

Step-8 Make a request to your application:
>> start the tomcat server by clicking on startup.batch file located inside the bin folder of your tomcat installation directory.
>>open any browser and type the following url  "http://localhost:8080/Sample/index.html "
     it will show your html page with a submit button which will call  Myservlet on clicking.

You are done,Good luck

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