Codelybrary: Java Servlet simple example

Monday, March 8, 2021

Java Servlet simple example

//Servlet file name 'RandomGreetings.java'.

//Run on NetBeans IDE 8.2

* A Servlet that returns a randomly chosen greeting from a list of five

* different greetings. The greetings must be stored as constant strings

* in the program.

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.util.Random;

@WebServlet(urlPatterns = {"/RandomGreetings"})

public class RandomGreetings extends HttpServlet

{

//Five greetings saved as constan strings

public static final String STR1 = "Good morning";

public static final String STR2 = "Good night";

public static final String STR3 = "Good afternoon";

public static final String STR4 = "Good day";

public static final String STR5 = "Welcome";

String[] arr = {STR1,STR2,STR3,STR4,STR5};

Random ran = new Random();

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException

{

int random = ran.nextInt(5);

String g = arr[random];

response.setContentType("text/html");

PrintWriter out = response.getWriter();

out.println("<!DOCTYPE html>");

out.println("<html>");

out.println("<head>");

out.println("<title>Random Greetings</title>");

out.println("</head>");

out.println("<body>");

out.println(g);

out.println("</body>");

out.println("</html>");

}

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

//Corresponding HTML index file (index.html)

<!DOCTYPE html>

<!--

A simple markup document to test the Servlet

-->

<html>

<head>

<title>Random Greetings</title>

</head>

<body>

<div>

Press the button to test the Servlet

</form>

</div>

</body>

</html>

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

//Project directory structure at location: C:\Users\ashu\Documents\NetBeansProjects\ServletE1

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

Output:

//On running the servlet, the IDE opens the 'index.html' page at url = http://localhost:8080/ServletE1/)

//Syntax of index page url = http://localhost:<port_numer>/<project_name>/

//Button click executes the servlet at url = http://localhost:8080/ServletE1/RandomGreetings?

//NOTE: You need to run each servlet file one by one in the project (if it has multiple servlet files/java files in the 'Source Packages' folder)

//Syntax for the servlet url = http://localhost:<port_number>/<project_number>/<servlet_file_name_without_.java_extension>?

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

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Monday, March 8, 2021

Java Servlet simple example

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