过滤器过滤一个包内所有servlet

先看下文件的目录结构:

我们要做的就是用MyFirstFilter过滤servlet包内的所有servlet即DisplayHeader、HelloServlet、SecondServlet。
主要就是两个注意事项:
1:

package servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class HelloServlet
 */
@WebServlet("/servlet/HelloServlet")
public class HelloServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public HelloServlet() {
        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

//      String msg = request.getInputStream().toString();
//      response.getWriter().println("��������");
        response.getWriter().println(request.getAttribute("ServletPath"));
        response.getWriter().println("公司的分公司");
//      request.setAttribute("name", "��������HelloServlet����Ϣmarhong");
//      request.getRequestDispatcher("/SecondServlet").forward(request, response);
    }

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

}

这里一定要注意就是那个注释部分:

它原来的值是:@WebServlet(“/HelloServlet”),一定要改成上图所示的才可以

2.就是web.xml了,代码如下所示:

<?xml version="1.0" encoding="UTF-8"?>  
<web-app version="2.5"   
    xmlns="http://java.sun.com/xml/ns/javaee"   
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee   
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">  
       <filter>
    <filter-name>MyFirstFilter</filter-name>
    <filter-class>com.util.MyFirstFilter</filter-class>
    <init-param>
    <param-name>encoding</param-name>
    <param-value>GBK</param-value>
    </init-param>
    <init-param>
    <param-name>secondAttribute</param-name>
    <param-value>filterConfig的第二个参数</param-value>
    </init-param>
    </filter>
    <filter-mapping>
    <filter-name>MyFirstFilter</filter-name>
    <url-pattern>/servlet/*</url-pattern>
   <url-pattern>/checkIn.jsp</url-pattern>
    </filter-mapping>
  <servlet>  
     <!-- 类名 -->  
    <servlet-name>HelloServlet</servlet-name>  
    <!-- 所在的包 -->  
    <servlet-class>servlet.HelloServlet</servlet-class>  
  </servlet>  
  <servlet-mapping>  
    <servlet-name>HelloServlet</servlet-name>  
    <!-- 访问的网址 -->  
    <url-pattern>/SummerTest/servlet/HelloServlet</url-pattern>  
    </servlet-mapping>  


    <servlet>

    <servlet-name>SecondServlet</servlet-name>
    <servlet-class>servlet.SecondServlet</servlet-class>
    </servlet>
     <servlet-mapping>  
    <servlet-name>SecondServlet</servlet-name>  
    <!-- 访问的网址 -->  
    <url-pattern>/SummerTest/servlet/SecondServlet</url-pattern>  

    </servlet-mapping> 
 <servlet>  
  <!-- 类名 -->  
  <servlet-name>DisplayHeader</servlet-name>  
  <!-- 所在的包 -->  
  <servlet-class>servlet.DisplayHeader</servlet-class>  
</servlet>  
<servlet-mapping>  
  <servlet-name>DisplayHeader</servlet-name>  
  <!-- 访问的网址 -->  
  <url-pattern>/SummerTest/servlet/DisplayHeader</url-pattern>  
</servlet-mapping> 
</web-app> 

注意这两个地方应该就可以达到目的了。