JAVA EE: Servlets : ServletConfig

Tuesday, 25 March 2014

Servlets : ServletConfig

Click here to watch in Youtube : https://www.youtube.com/watch?v=cfwI_bdwQa4

Click the below Image to Enlarge

ServletConfig

ServletConfig Project Dir Structure

ServletConfig

ServletConfigServlet.java

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

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

public class ServletConfigServlet extends HttpServlet
{

  private static final long serialVersionUID = 1L;

  ServletConfig             servletConfig           = null;

  public void init( ServletConfig servletConfig )
  {
    this.servletConfig = servletConfig;
    System.out.println("\n-----------------------------------------------------");
    System.out.println("init method has been called and servlet is initialized");
    System.out.println("-----------------------------------------------------");

    System.out.println("Using 'getInitParameter(String name)' method get the value");
    String driverName = servletConfig.getInitParameter("driverName");
    System.out.println("Driver Name : " + driverName);

    System.out.println("\nUsing 'getInitParameterNames()'  method get the value");
    Enumeration<String> paramNames = servletConfig.getInitParameterNames();

    while( paramNames.hasMoreElements() )
    {
      String paramName = paramNames.nextElement();

      String value = servletConfig.getInitParameter(paramName);

      System.out.println("paramName : " + paramName + ", Value: " + value);

    }

  }

  public void doGet( HttpServletRequest request, HttpServletResponse response ) throws ServletException,
                  IOException
  {

    System.out.println("\n-----------------------------------------------------");
    System.out.println("doGet method has been called");
    System.out.println("-----------------------------------------------------");

    ServletConfig servletConfig = getServletConfig();
    System.out.println("Got servletconfig object using getServletConfig() method : " + servletConfig);
    System.out.println("Servlet Name : " + servletConfig.getServletName());
    System.out.println("ServletContext Object : " + servletConfig.getServletContext());

    response.setContentType("text/html");
    PrintWriter out = response.getWriter();
    out.print("<html><body>");
    out.print("<b>hello HTTP servlet</b>");
    out.print("</body></html>");
  }

  public void destroy()
  {
    System.out.println("-----------------------------------------------------");
    System.out.println("destroy method has been called and servlet is destroyed");
    System.out.println("-----------------------------------------------------");
  }

  public ServletConfig getServletConfig()
  {
    return servletConfig;
  }
}

web.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" metadata-complete="true" version="3.0">
  <display-name>ServletConfigServlet</display-name>
  <description>
        This is a simple web application with a source code organization
        based on the recommendations of the Application Developer's Guide.
    </description>
  <servlet>
    <servlet-name>ServletConfigServlet</servlet-name>
    <servlet-class>ServletConfigServlet</servlet-class>
    
     <init-param>  
      <param-name>driverName</param-name>  
      <param-value>oracle.jdbc.driver.OracleDriver</param-value>  
    </init-param>
    
     <init-param>  
      <param-name>username</param-name>  
      <param-value>ram</param-value>  
    </init-param>
    
    <init-param>  
      <param-name>password</param-name>  
      <param-value>ram</param-value>  
    </init-param>   
    
  </servlet>
  
  <servlet-mapping>
    <servlet-name>ServletConfigServlet</servlet-name>
    <url-pattern>/servletConfig</url-pattern>
  </servlet-mapping>
</web-app>

index.html

<!DOCTYPE HTML><html lang="en"><head>
<meta charset="UTF-8">
<title>ServletConfigServlet</title>
</head>
<body>
<p>
<h3>ServletConfigServlet</H3>
<p></p>
<ul>

<li><a href="servletConfig">ServletConfigServlet</a></li>

</ul>
</body></html>

Environment Used:

JDK version :1.6.0_30
Tomcat version : 7.0.50

To Download ServletConfigApp Project Click the below link

https://sites.google.com/site/javaee4321/servlets/ServletConfigApp.zip?attredirects=0&d=1

See also:

Servlets Tutorial

All Design Patterns Links