Unit08： 过滤器、监听器

　　　　Unit08： 过滤器、监听器　　　　

下面这些小案例主要演示的filter的执行时机：

web

package web;

import java.io.IOException;

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

public class AddCostServlet extends HttpServlet {

    @Override
    protected void service(
        HttpServletRequest req, 
        HttpServletResponse res) throws ServletException, IOException {
        System.out.println("增加资费");
    }

}

AddCostServlet.java