Java application to demonstrate servlet life cycle
Write a Java program to demonstrate servlet life cycle.
Servlet life cycle has 3 stages
- Initialization
- Service
- Destroy
There are 3 methods in servlet which will get executed automatically once the servlet enters in above stages.
init() : This method will get executed when servlet get initialized.
service() : This method will get executed when servlet starts handling the request. The request can be in form of POST, GET, etc.
destroy() : This method will get executed when servlet is been destroyed.
Java servlet life cycle
index.html
1 2 3 4 5 6 7 8 9 10 11 12 | <html> <head> <title>Servlet Life Cycle</title> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> </head> <body> <form action="ServletLifeCycleDemo" method="get"> <input type="submit" value="Click Here"> </form> </body> </html> |
ServletLifeCycleDemo.java (Servlet File)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; @WebServlet(urlPatterns = {"/ServletLifeCycleDemo"}) public class ServletLifeCycleDemo extends HttpServlet { @Override public void init() throws ServletException { System.out.println("Servlet has been Initialized..."); } @Override public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException { PrintWriter out = res.getWriter(); out.println("Servlet Life Cycle Has three stages n1. Initializationn2. Servicen3. Destroy"); System.out.println("Servlet started servicing..."); } @Override public void destroy() { System.out.println("Servlet has been Destroyed..."); } } |
Output
After clicking on the “Click Here” button servlet will start running.
We can see in console that init() and service() method has been executed. These will get executed when the servlet is called.
If we stop the server or restart the server it will force servlet to stop, which means servlet will get destroyed hence servlet will run destroy().
PRACTICALS/PRACTICE PROGRAM IN Java
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