servlet上下文参数

配置Servlet上下文
任何servlet都可以访问Servlet上下文参数，

<web-app>
     <context-param>
        <param-name>contextParam</param-name>
        <param-value>Hello Servlet</param-value>
      </context-param>
      <!--省略其他配置-->
   </web-app>    

servlet参数与servlet上下文参数获取方式的差别

 String initParam = getInitParameter("initParam");
 String contextParam = this.getServletContext().getInitParameter("contextParam");
 System.out.println("Servlet初始化参数“+initParam);
 System.out.println("系统初始化参数”+contextParam）;