web.xml里面可以定義兩種參數(shù):
(1)application范圍內(nèi)的參數(shù),存放在servletcontext中,在web.xml中配置如下:
<context-param>
<param-name>context/param</param-name>
<param-value>avalible during application</param-value>
</context-param> (2)servlet范圍內(nèi)的參數(shù),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中可以通過代碼分別取用:
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("下面的兩個參數(shù)param1是在servlet中存放的");
System.out.println(this.getInitParameter("param1"));
System.out.println("下面的參數(shù)是存放在servletcontext中的");
System.out.println(getServletContext().getInitParameter("context/param"));
}
}
第一種參數(shù)在servlet里面可以通過getServletContext().getInitParameter("context/param")得到
第二種參數(shù)只能在servlet的init()方法中通過this.getInitParameter("param1")取得
理解能力有些問題,才弄明白他們之間的關(guān)系。