web.xml中在Servlet中获取context-param和init-param内的参数

web.xml里面可以定义两种参数：
1.application范围内的参数，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范围内的参数，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中可以通过代码分别取用：

package com.qisentech.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(this.getInitParameter("param1"));
System.out.println(getServletContext().getInitParameter("context/param"));
}
}

第一种参数在servlet里面可以通过getServletContext().getInitParameter("context/param")得到
第二种参数只能在servlet的init()方法中通过this.getInitParameter("param1")取