Web xml Filtering

                WEB.XML FILTERING EXAMPLE

    Filtering is related with pre-processing. Before you go into your page you can do manipulation with your data. This mapping is defined in web.xml file of your project. And you can open a java file at the appropriate package with the suitable interface and you must implement its methods correctly. For example :

<filter>

  <filter-name>coding</filter-name>

  <filter-class>com.example.code.Coding</filter-class>

  <init-param>

   <param-name>coding</param-name>

   <param-value>ISO-8859-1</param-value>

  </init-param>

 </filter>

<filter-mapping>

        <filter-name> coding </filter-name>

        <url-pattern>/*</url-pattern>

</filter-mapping>

     You can declare your filter that you use for the pre processor for your each request for example in Struts framework if you have an action mapping for the path of url, you can jump into the filter before action class. For example in this example code for each request with any of the url parameters get into the filter name and this filter name maps the action to the filter class that you can pre process somethink before action. Your filter class in the appropriate package implements Filter as in the example code below.

package com.example.code;

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;

public class Coding implements Filter{

       @Override

       public void destroy() {

              // TODO Auto-generated method stub

       }

       @Override

       public void doFilter(ServletRequest arg0, ServletResponse arg1,

                     FilterChain arg2) throws IOException, ServletException {

              // TODO Auto-generated method stub

              System.out.println("Now in Filter You can Pre process in here");

              arg2.doFilter(arg0, arg1);

       }

       @Override

       public void init(FilterConfig arg0) throws ServletException {

              // TODO Auto-generated method stub

             

       }

}

For example if you start your server and go into one of your page from url you can see from console the result of test.