Java Programming History Part-8
Posted: Sun Apr 22, 2012 2:36 pm
Example
The following example servlet prints how many times its service() method was called. Note that HttpServlet is a subclass of GenericServlet, an implementation of the Servlet interface. The service() method of HttpServlet class dispatches requests to the methods doGet(), doPost(), doPut(), doDelete(), and so on; according to the HTTP request. In the example below method service() is overridden and does not distinguish which HTTP request method it serves.
Usage
(a) Process or store data that was submitted from an HTML form.
(b) Provide dynamic content such as the results of a database query.
(c) Manage state information that does not exist in the stateless HTTP protocol, such as filling the articles into the shopping cart of the appropriate customer.
N:B:-see more again.
The following example servlet prints how many times its service() method was called. Note that HttpServlet is a subclass of GenericServlet, an implementation of the Servlet interface. The service() method of HttpServlet class dispatches requests to the methods doGet(), doPost(), doPut(), doDelete(), and so on; according to the HTTP request. In the example below method service() is overridden and does not distinguish which HTTP request method it serves.
Code: Select all
import java.io.IOException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ServletLifeCycleExample extends HttpServlet {
private int count;
@Override
public void init(ServletConfig config) throws ServletException {
super.init(config);
getServletContext().log("init() called");
count=0;
}
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
getServletContext().log("service() called");
count++;
response.getWriter().write("Incrementing the count: Count = "+count);
}
@Override
public void destroy() {
getServletContext().log("destroy() called");
}
}
.........................................................................................................................
Servlets are most often used to (a) Process or store data that was submitted from an HTML form.
(b) Provide dynamic content such as the results of a database query.
(c) Manage state information that does not exist in the stateless HTTP protocol, such as filling the articles into the shopping cart of the appropriate customer.
N:B:-see more again.