Writing First Servlet HelloWorld Web Application ~ foundjava

HelloWorld Servlet Web Application

Developing HelloWorld Servlet Web Application is easy and requires only 2 files. In this tutorial, folder structure, web.xml, servlet class are provided.

Folder Structure

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webapps

       |_ helloworldservlet

                       |_ WEB-INF

                                  |_ classes

                                           |_ HelloWorld.java

                                           |_ HelloWorld.class

                                  |_ web.xml

web.xml

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<web-app>
<servlet>
<servlet-name>myservlet</servlet-name>
<servlet-class>HelloWorld</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>myservlet</servlet-name>
<url-pattern>/hw</url-pattern>
</servlet-mapping>
</web-app>

HelloWorld.java

---------------------------------

import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;
public class HelloWorld extends HttpServlet
{
public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException
{
PrintWriter pw=res.getWriter();
res.setContentType("text/html");
pw.println("<h1>Hello World!</h1>");
}
}

javax.servlet.http.*: Contains HttpServlet, HttpServletRequest, HttpServletResponse classes (used here).

javax.servlet.*: Contains ServletException (used here).

java.io.*: Contains PrintWriter, IOException (used here).

doGet(): For url type submission, submission through url.

PrintWriter: Part of the java.io package.

res.setContentType("text/html"): Set content type to html, because the page is html. Optional.

pw.println("<h1>Hello World!</h1>"): Present in the PrintWriter class, write HelloWorld! within <h1> (here).