Servlet instance

A Java Servlet is a program that runs on a Web server or application server as an intermediary layer between requests from a Web browser or other HTTP client and a database or application on the HTTP server.

Using Servlets, you can collect user input from web forms, render records from a database or other sources, and dynamically create web pages.

Servlet instance syntax

Servlet is a Java class that serves HTTP requests and implements the javax.servlet.Servlet interface. Web application developers typically write servlets that extend javax.servlet.http.HttpServlet and implement abstract classes of the Servlet interface specifically to handle HTTP requests.

Servlet instance example

//Import the necessary java libraries
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
//Extend HttpServlet class
public class HelloWorld extends HttpServlet {
​
private String message;
public void init() throws ServletException
{
             // Perform necessary initialization
                                        message =          
}
public void doGet(HttpServletRequest request,
HttpServletResponse response)
                  throws ServletException, IOException
{
          // Set response content type
       response.setContentType("text/html");
//The actual logic is here
PrintWriter out = response.getWriter();
out.println("<h1>" + message + "</h1>");
}
​
public void destroy()
{
      // do nothing
}}