web.xml配置引數context-param和init-param的區別

<context-param>   
           <param-name>context/param</param-name>   
           <param-value>avalible during application</param-value>   
</context-param>

 
(2)servlet範圍內的引數，只能在servlet的init()方法中取得，在web.xml中配置如下：

<servlet>   
    <servlet-name>MainServlet</servlet-name>   
    <servlet-class>com.wes.controller.MainServlet</servlet-class>   
    <init-param>   
       <param-name>param1</param-name>   
       <param-value>avalible in servlet init()</param-value>   
    </init-param>   
    <load-on-startup>0</load-on-startup>   
</servlet> 

 在servlet中可以通過程式碼分別取用：

Java程式碼  

1. package com.wes.controller;       
2.       
3. import javax.servlet.ServletException;       
4. import javax.servlet.http.HttpServlet;       
5.       
6. public class MainServlet extends HttpServlet{       
7.       
8.     public MainServlet(){       
9.         super();       
10.       }       
11.     public void init() throws ServletException ...{       
12.           System.out.println("下面的兩個引數param1是在servlet中存放的");       
13.           System.out.println(this.getInitParameter("param1"));       
14.           System.out.println("下面的引數是存放在servletcontext中的");       
15.           System.out.println(getServletContext().getInitParameter("context/param"));       
16.        }       
17. }  

package com.wes.controller;    
   
import javax.servlet.ServletException;    
import javax.servlet.http.HttpServlet;    
   
public class MainServlet extends HttpServlet{    
   
    public MainServlet(){    
        super();    
      }    
    public void init() throws ServletException ...{    
          System.out.println("下面的兩個引數param1是在servlet中存放的");    
          System.out.println(this.getInitParameter("param1"));    
          System.out.println("下面的引數是存放在servletcontext中的");    
          System.out.println(getServletContext().getInitParameter("context/param"));    
       }    
}

 第一種引數在servlet裡面可以通過getServletContext().getInitParameter("context/param")得到

在JSP中可以用config.getServletContext().getInitParameter("context/param")得到

或者this.getServletContext().getInitParameter("context/param")

第二種引數只能在servlet的init()方法中通過this.getInitParameter("param1")取得.