Steps to create a servlet example
There
are given 6 steps to create a servlet example. These steps are
required for all the servers.
The servlet example can be created by three ways:
1.
By implementing Servlet interface,
2.
By inheriting GenericServlet class,
(or)
3.
By inheriting HttpServlet class
The
mostly used approach is by extending HttpServlet because it provides http
request specific method such as doGet(), doPost(), doHead() etc.
we
are going to use apache tomcat server in this example. The
steps are as follows:
1.
Create a directory structure
2.
Create a Servlet
3.
Compile the Servlet
4.
Create a deployment descriptor
5.
Start the server and deploy the
project
6.
Access the servlet
1)Create a directory structures
The directory
structure defines that where to put the different types of files so
that web container may get the information and respond to the client.
The directory
structure defines that where to put the different types of files so
that web container may get the information and respond to the client.
The
Sun Microsystem defines a unique standard to be followed by all the server
vendors. Let's see the directory structure that must be followed to create the
servlet.
 |
| Fig: Step To Create Servlet Example |
2)Create a Servlet
There
are three ways to create the servlet.
In
this example we are going to create a servlet that extends the
DemoServlet.java
import javax.servlet.http.*;
3)Compile the servlet
For compiling the Servlet, jar file is required
to be loaded.
There
are three ways to create the servlet.
1.
By implementing the Servlet interface
2.
By inheriting the GenericServlet class
3.
By inheriting the HttpServlet class
The
HttpServlet class is widely used to create the servlet because it
provides
methods to handle http requests such as doGet(), doPost,
doHead() etc.
|
In
this example we are going to create a servlet that extends the
HttpServlet class. In this example, we are
inheriting the HttpServlet
class
and providing the implementation of the doGet() method.
Notice that get request is the default
request.
|
DemoServlet.java
import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;
public class DemoServlet extends HttpServlet{
public void doGet(HttpServletRequest req,HttpServletResponse res)
throws ServletException,IOException
{
res.setContentType("text/html");//setting the content type
PrintWriter pw=res.getWriter();//get the stream to write the data
//writing html in the stream
pw.println("<html><body>");
pw.println("Welcome to servlet");
pw.println("</body></html>");
pw.close();//closing the stream
} }
3)Compile the servlet
Two ways to load the jar file
1.
set
classpath
4)Create the deployment descriptor (web.xml file)
The deployment
descriptor is an xml file, from which Web Container gets the
information about the servet to be invoked.
web.xml file
<web-app>
<servlet>
<servlet-name>sonoojaiswal</servlet-name>
<servlet-class>DemoServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>sonoojaiswal</servlet-name>
<url-pattern>/welcome</url-pattern>
</servlet-mapping>
</web-app>
5)Start the Server and deploy the project
To
start Apache Tomcat server, double click on the startup.bat file under
apache-tomcat/bin directory.
6) How to access the servlet
Open broser and
write http://hostname:portno/contextroot/urlpatternofservlet
For example:
http://localhost:9999/demo/welcome
Hello, my name is Pramod Dwivedi. I'm a 5 year old self-employed in online business Industry.
No comments:
Post a Comment