Getting Started with filter

Testfilter.java

Package com.cdsxt.filter;

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;

/**
* @author Administrator
* Test Filter
*
* Implementation of a specific interface
*/
public class Testfilter implements filter{

The filter's Init method is loaded by default as the server starts to load

@Override
public void init (Filterconfig filterconfig) throws Servletexception {
TODO auto-generated Method Stub
System.out.println ("Testfiler.init ()");

}

@Override
public void DoFilter (ServletRequest request, Servletresponse Response,filterchain chain) throws IOException, servletexception {
TODO auto-generated Method Stub
System.out.println ("Testfiler.dofilter ()");
Chain.dofilter (request, response);
System.out.println ("Testfiler1.dofilter ()");
}

@Override
public void Destroy () {
TODO auto-generated Method Stub
System.out.println ("Testfiler.destroy ()");
}

}

Testfilter1.java

Package com.cdsxt.filter;

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;

/**
* @author Administrator
* Test Filter
*
* Implementation of a specific interface
*/
public class TestFilter1 implements filter{

Filter is loaded by default

@Override
public void init (Filterconfig filterconfig) throws Servletexception {
TODO auto-generated Method Stub
System.out.println ("testfiler.init1 ()");

}

@Override
public void DoFilter (ServletRequest request, Servletresponse Response,filterchain chain) throws IOException, servletexception {
TODO auto-generated Method Stub
System.out.println ("Testfiler.dofilter1 ()");
SYSTEM.OUT.PRINTLN (Request instanceof HttpServletRequest);

}

@Override
public void Destroy () {
TODO auto-generated Method Stub
System.out.println ("testfiler.destroy1 ()");
}

}

Loginfilter.java

Package com.cdsxt.filter;

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;
Import javax.servlet.http.HttpSession;

Import Com.cdsxt.po.Users;

public class Loginfilter implements filter{

@Override
public void init (Filterconfig filterconfig) throws Servletexception {
TODO auto-generated Method Stub

}

@Override
public void DoFilter (ServletRequest request, servletresponse response,
Filterchain chain) throws IOException, Servletexception {
/**
* If the request is logged in, then go directly or jump to the login page
*/
HttpServletRequest req = (httpservletrequest) request;
HttpServletResponse resp = (httpservletresponse) response;
Get the session to determine if there are users in the session
HttpSession session = Req.getsession ();

String uri = Req.getrequesturi ();

Object users = Session.getattribute ("admin");
Logged-On
if (users!=null && users instanceof users) {
Chain.dofilter (request, response);
}else{
if (Uri.endswith ("login.jsp") | | | uri.endswith ("logincontroller") | | uri.endswith (". css") | | uri.endswith (". js") | | Uri.endswith (". jpg")) {
Chain.dofilter (request, response);
}else{
Resp.sendredirect (Req.getcontextpath () + "/views/login.jsp");
}
}
}

@Override
public void Destroy () {
TODO auto-generated Method Stub

}

}

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_2_5.xsd "id=" webapp_id "version=" 2.5 ">
<display-name>LoginSystem</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>


<!--

The order in which the filter is executed is related to the order of the declared filter-mapping from the top down
-
<!--<filter>
<filter-name>test-filter</filter-name>
<filter-class>com.cdsxt.filter.TestFilter</filter-class>
</filter>

<filter>
<filter-name>test-filter1</filter-name>
<filter-class>com.cdsxt.filter.TestFilter1</filter-class>
</filter>
<filter-mapping>
<filter-name>test-filter1</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

<filter-mapping>
<filter-name>test-filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

<filter>
<filter-name>login-filter</filter-name>
<filter-class>com.cdsxt.filter.LoginFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>login-filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter>
<filter-name>logout-filter</filter-name>
<filter-class>com.cdsxt.filter.LogoutFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>logout-filter</filter-name>
<url-pattern>/logout</url-pattern>
</filter-mapping>

<servlet>
<description></description>
<display-name>UsersController</display-name>
<servlet-name>UsersController</servlet-name>
<servlet-class>com.cdsxt.controller.UsersController</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UsersController</servlet-name>
<url-pattern>/users/usersController</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>LoginController</servlet-name>
<servlet-class>com.cdsxt.controller.LoginController</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginController</servlet-name>
<url-pattern>/login/loginController</url-pattern>
</servlet-mapping>
</web-app>

Getting Started with filter