1.config实质上是ServletConfig的一个实例

2.config常用来获取Servlet的初始化参数

web.xml

       
         
            
        
         index.jsp
           
       
        
            
        
         config
             
        
         com.test.servlet.Config
             
                 
         
          name
                  
         
          小翁
              
             
                 
         
          age
                  
         
          22
              
         
        
            
        
         config
             
        
         /config
         
        
      

　　

Config.java

package com.test.servlet;import java.io.IOException; import java.io.PrintWriter;import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;public class Config extends HttpServlet {    /**      *      */     private static final long serialVersionUID = 1L;    @Override     protected void doGet(HttpServletRequest req, HttpServletResponse resp)             throws ServletException, IOException {         this.doPost(req, resp);     }    @Override     protected void doPost(HttpServletRequest req, HttpServletResponse resp)             throws ServletException, IOException {         resp.setContentType("text/html;charset=utf-8");         ServletConfig config = getServletConfig();         String name = config.getInitParameter("name");         String age = config.getInitParameter("age");         PrintWriter out = resp.getWriter();         out.println(name+"今年"+age+"岁！");     }         }