Servlets : Multiple Filter Demo

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MultilpleFiltersDemo Project Dir Structure

LogFilter.java

import java.io.IOException;
import java.util.Date;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

public class LogFilter implements Filter
{

    public void init(FilterConfig config) throws ServletException
    {
        System.out
                .println("------------------------------------------------------");
        System.out.println(" init method is called in "
                + this.getClass().getName());
        System.out
                .println("------------------------------------------------------");
    }

    public void doFilter(ServletRequest req, ServletResponse res,
            FilterChain chain) throws IOException, ServletException
    {

        System.out.println(" doFilter method is called in "
                + this.getClass().getName() + "\n\n");

        HttpServletRequest request = (HttpServletRequest) req;

        // Get the IP address of client machine.
        String ipAddress = request.getRemoteAddr();

        // Log the IP address and current timestamp.
        System.out.println("IP " + ipAddress + ", Time "
                + new Date().toString() + "\n\n");

        chain.doFilter(req, res);

    }

    public void destroy()
    {
        // add code to release any resource
        System.out
                .println("------------------------------------------------------");
        System.out.println(" destroy method is called in "
                + this.getClass().getName());
        System.out
                .println("------------------------------------------------------");
    }
}

AuthenticationFilter.java

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class AuthenticationFilter implements Filter
{

    public void init(FilterConfig config) throws ServletException
    {
        System.out
                .println("------------------------------------------------------");
        System.out.println(" init method is called in "
                + this.getClass().getName());
        System.out
                .println("------------------------------------------------------");
    }

    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException
    {
        System.out.println(" doFilter method is called in "
                + this.getClass().getName() + "\n\n");

        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse res = (HttpServletResponse) response;

        String userName = req.getParameter("username");
        String passWord = req.getParameter("password");

        if (!(userName.equalsIgnoreCase("ram") && passWord.equals("ram")))
        {
            System.out
                    .println("######################################################");
            System.out.println("Unauthorized request");
            System.out
                    .println("######################################################\n\n");
            res.sendRedirect("index.html");
        }
        else
        {
            // pass the request along the filter chain
            chain.doFilter(request, response);
        }

    }

    public void destroy()
    {
        // add code to release any resource
        System.out
                .println("------------------------------------------------------");
        System.out.println(" destroy method is called in "
                + this.getClass().getName());
        System.out
                .println("------------------------------------------------------");
    }
}

HelloWorldServlet.java

import java.io.IOException;
import java.io.PrintWriter;

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

public class HelloWorldServlet extends HttpServlet
{

    private static final long serialVersionUID = 1L;

    public void init() throws ServletException
    {
        System.out
                .println("------------------------------------------------------");
        System.out.println(" Init method is called in "
                + this.getClass().getName());
        System.out
                .println("------------------------------------------------------");
    }

    // Method to handle GET method request.
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException
    {

        System.out.println(" doGet method is called in "
                + this.getClass().getName() + "\n\n");
        System.out
                .println("------------------------------------------------------");

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.print("Hello World <br>");

    }

    public void destroy()
    {
        System.out
                .println("------------------------------------------------------");
        System.out.println(" destroy method is called in "
                + this.getClass().getName());
        System.out
                .println("------------------------------------------------------");
    }
}

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>MultilpleFiltersDemo</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>hello</servlet-name>
        <servlet-class>HelloWorldServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>hello</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>

    <filter>
        <filter-name>LogFilter</filter-name>
        <filter-class>LogFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>LogFilter</filter-name>
        <url-pattern>/hello</url-pattern>
    </filter-mapping>

    <filter>
        <filter-name>AuthFilter</filter-name>
        <filter-class>AuthenticationFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>AuthFilter</filter-name>
        <url-pattern>/hello</url-pattern>
    </filter-mapping>

</web-app>

index.html

<!DOCTYPE HTML>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Multiple Filters Demo</title>
</head>
<body>
    <form action="hello" method="GET">
        
        UserName :  <input type="text" name="username" /><br /> 
        
        Password :&nbsp; &nbsp; <input type="password" name="password" /><br /> 
            
        <input type="submit" value="login" />
        
    </form>
</body>
</html>

Environment Used

JDK version :1.6.0_30
Tomcat version : 7.0.50

To Download MultilpleFiltersDemoApp Project Click the below link

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

See also:

Servlets Tutorial

All Design Patterns Links