728x90 AdSpace

Saturday, 5 April 2014

Servlet – Read Context Param using ServletContext Interface

In this tutorial we are going to see about, how to read Context param using ServletContext interface. In previous tutorials I explained about ServletContext interface with example program (read single context-param).Click here to read more about Servlet Context Interface.
1. Create new Dynamic web project by choosing File –> New –> Dynamic Web Project .
2. Create the Project called ServletExample as given below.
Servlet-dynamic web project
3. Create package called com.javatutorialscorner.servlet under ServletExample.
4. Create Servlet called ServletContextExample as shown in figure.
Create Servlet
http servlet
5. Click Next it will show URL mapping.You can edit Servlet URL if you need.
6. Click Next it will show methods available  in HttpServlet. Select appropriate method you need.
http servlet Services
7. By default your servlet will be mapped in web.xml, if your servlet not mapped in your web.xml use the following configuration to map the servlet in your web.xml
Servlet Mapping
<servlet>
    <servlet-name>Your Servlet Name</servlet-name>
    <servlet-class>Fully Qulaified Servlet Class Name</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Your Servlet Name</servlet-name>
    <url-pattern>/URL to Call Servlet</url-pattern>
  </servlet-mapping> 

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
 id="WebApp_ID" version="3.0">
 <display-name>ServetExample</display-name>
 <welcome-file-list>
  <welcome-file>index.html</welcome-file>
  <welcome-file>index.htm</welcome-file>
  <welcome-file>index.jsp</welcome-file>
  <welcome-file>default.html</welcome-file>
  <welcome-file>default.htm</welcome-file>
  <welcome-file>default.jsp</welcome-file>
 </welcome-file-list>
 <servlet>
  <servlet-name>ServletContextExample</servlet-name>
  <servlet-class>com.javatutorialscorner.servlet.ServletContextExample</servlet-class>

 </servlet>
 <context-param>
  <param-name>dbname</param-name>
  <param-value>jtctutorials</param-value>
 </context-param>
 <context-param>
  <param-name>images</param-name>
  <param-value>jtc/images</param-value>
 </context-param>
 <context-param>
  <param-name>skin</param-name>
  <param-value>jtc/css</param-value>
 </context-param>
 <context-param>
  <param-name>js</param-name>
  <param-value>jtc/script</param-value>
 </context-param>
 <servlet-mapping>
  <servlet-name>ServletContextExample</servlet-name>
  <url-pattern>/ServletContextExample</url-pattern>
 </servlet-mapping>
</web-app>

8. Add the required code inside doGet() method.

ServletContextExample.java

package com.javatutorialscorner.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class ServletContextExample
 */

public class ServletContextExample extends HttpServlet {
 private static final long serialVersionUID = 1L;

 /**
  * @see HttpServlet#HttpServlet()
  */
 public ServletContextExample() {
  super();
  // TODO Auto-generated constructor stub
 }

 /**
  * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
  *      response)
  */
 protected void doGet(HttpServletRequest request,
   HttpServletResponse response) throws ServletException, IOException {
  // TODO Auto-generated method stub

  response.setContentType("text/html");
  PrintWriter writer = response.getWriter();
  writer.write("<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\">\n"
    + "<html><head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=ISO-8859-1\"><title>Java Tutorials Corner - Servlet - Read Context Param using ServletContext </title>"
    + "</head><body><h1>Java Tutorials Corner - Servlet - Read Context Param using ServletContext</h1><table>");
  writer.write("<tr><td> Param Name </td><td> Param Value</td></tr>");

  ServletContext servletContext = getServletContext();
  Enumeration<String> contextParams = servletContext
    .getInitParameterNames();

  while (contextParams.hasMoreElements()) {
   String paramName = (String) contextParams.nextElement();
   writer.write("<tr><td> " + paramName + "</td><td>"
     + servletContext.getInitParameter(paramName) + "</td></tr>");
  }

  writer.write("</table></body></html>");
 }

 /**
  * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
  *      response)
  */
 protected void doPost(HttpServletRequest request,
   HttpServletResponse response) throws ServletException, IOException {
  // TODO Auto-generated method stub
 }

}

9. Now save and Run the servlet, Run As –> Run on Server – Select your web Server to run the servlet. ( see How to configure tomcat in eclipse) 
http://www.javatutorialcorner.com/2014/03/how-to-configure-tomcat-in-eclipse.html

10.call the URL which is mapped in web.xml.

http://localhost:8080/ServletExample/ServletContextExample

Output

image
Annamalai Thangaraj

Annamalai is working as Technical Lead in Leading Telecom company with 5+ years experience in Identity and Access Management , Telecom and Networks, BigData, Java, Spring, Struts, Hibernate, AngularJS, and Enterprise Web Application Development.

Website: Java Tutorials Corner

Shop and help us

Flipkart Offer Snapdeal offer Amazon.in offer Amazon.com offer
  • Blogger Comments
  • Facebook Comments
  • Disqus Comments

0 comments:

Post a Comment

Item Reviewed: Servlet – Read Context Param using ServletContext Interface Rating: 5 Reviewed By: Annamalai Thangaraj