------------ContextServlet.java--------------节选--

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  // TODO Auto-generated method stub
  request.setCharacterEncoding("GB2312");
  response.setContentType("text/html;charset=gb2312");
  PrintWriter out = response.getWriter();
  ServletContext context = getServletConfig().getServletContext();
  //获得工程相关信息
  out.println("获得了工程的相对路径："+context.getRealPath("/")+"<br>");
  out.println("获取了Tomcat的信息: "+context.getServerInfo()+"<br>");
  out.println("获取了JNDI："+context.getResource("/")+"<br>");
  out.println("获取了源程序的相对路径："+context.getResourcePaths("/")+"<br>");
  //getInitParameter方法
  String date = context.getInitParameter("date");
  String myclass = context.getInitParameter("class");
  out.println("date is -- "+date+"<br>");
  out.println("class is -- "+myclass+"<br>");
  //集合方法
  Enumeration e = context.getInitParameterNames();
  while(e.hasMoreElements()){
   String pName=(String) e.nextElement();
   String pValue=context.getInitParameter(pName);
   out.println("<br><b>"+pName+"</b>&nbsp;");
   out.println("----- "+pValue+"<br>");
  }
 }

-------------------web.xml----------------------

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>test4-03</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <context-param>
   <param-name>date</param-name>
   <param-value>200</param-value>
  </context-param>
  <context-param>
   <param-name>class</param-name>
   <param-value>102</param-value>
  </context-param>
  <servlet>
   <description>This is the description of my J2EE component</description>
   <display-name>This is the display name of my J2EE component</display-name>
   <servlet-name>ContextServlet</servlet-name>
   <servlet-class>com.ContextServlet</servlet-class>
   <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
   <servlet-name>ContextServlet</servlet-name>
   <url-pattern>/servlet/ContextServlet</url-pattern>
  </servlet-mapping>
</web-app>