Java Servlet Programing Laungage

Java Servlet Projects

Servlet Project 3

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Create an application for generate alphabet triangle through Servlet
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In this Generic Servlet program, a alphabet triangle is generated and picks five random alphabet through list.

Web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
  xmlns="http://java.sun.com/xml/ns/javaee" 
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
  http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
  <servlet>
     <servlet-name>alphabetTriangleServlet</servlet-name>
     <servlet-class>r4r.GenericServlet.alphabetTriangleServlet</servlet-class>
  </servlet>
  <servlet-mapping>
      <servlet-name>alphabetTriangleServlet</servlet-name>
	  <url-pattern>/alphabetTriangleServlet</url-pattern>
  </servlet-mapping>
  <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
</web-app>

Index.jsp

<%-- 
    Document   : index.jsp
--%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <title>r4r.co.in-GenericServlet</title>
 </head>
 <body>
   <form>
   <h1>Access GenericServlet by servlet's Name!</h1>
   <a href="alphabetTriangleServlet">alphabetTriangleServlet</a>
   </form>
 </body>
</html>

Servlet Program


/*
 * Save as a alphabetTriangleServlet.java
 */
package r4r.GenericServlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import javax.servlet.GenericServlet;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
/**
 *
 * @author R4R
*/
public class alphabetTriangleServlet 
	extends GenericServlet {

    //declaration and initialization 
    private ArrayList<String> arrayList = new ArrayList<String>();
    char ascii[] = new char[28];

    @Override
    public void init() throws ServletException {
   // Provide alphabet ascii code range 
   for (int i = 0, a = 65; a < 91; a++) {
  ascii[i] = (char) a;
  i++;    //increment value 
   }
    }

    @Override
    public void service(ServletRequest req,
	 ServletResponse res)throws ServletException,IOException
	{
     res.setContentType("text/html;charset=UTF-8");
     PrintWriter out = res.getWriter();
     try {
       //Invoke method
         processHeader(out);
         processRequest(out);
          processFooter(out);
          }
	finally
	{
        out.close();  // free resource
    }
    }

    //Method handle Form Header
    protected void processHeader(PrintWriter out) {
   out.println("<html>");
   out.println("<head>");
   out.println("<title>" + getServletInfo() + "</title>");
   out.println("</head>");
   out.println("<body>");
   out.println("<h1>Servlet alphabetTriangleServlet</h1>");
    }

    // Method handle Form Center
    protected void processRequest(PrintWriter out) {

   // Generate Alphabet value and store all value into array
   System.out.println("Alphabet Generate :\n");
   int count = 0;
   for (int i = 0; i < 26; i++) {
  String string = "'" + ascii[count++] + "'" + " ";
  arrayList.add(string);
   }
   out.println("Alphabet Generate : " + "<b>" + arrayList + "</b><BR>");

   //Generate Alphabet triangle on browser
   out.println("<hr align=\"left\" width=\"50%\"/>");
   out.println("Alphabet Triangle Generate: <BR><BR>");
   int count1 = 0;
   for (int i = 0; i < 7; i++) {
  for (int j = 0; j <= i; j++) {
 out.print("<b><I>" + ascii[count1++] + "</I></b>"); 
  }
  out.print("<BR>");
   }

   //Pick 5 random alphabet from List
   out.println("<hr align=\"left\" width=\"50%\"/>");
   out.println("Pick 5 random alphabet from List :");
   //Shuffle array value 
   Collections.shuffle(arrayList); 
   for (int i = 0; i < 5; i++) {
  String value = arrayList.get(i);
  out.println("<b>" + value + "</b>" + " ");
   }
    }

    // Method handle Form Footer
    protected void processFooter(PrintWriter out) {
   out.println("</body>");
   out.println("</html>");
    }

    @Override
    public String getServletInfo() {
   return "r4r.co.in- alphabetTriangleServlet";
    }
}

Output of Program
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