以下内容引用自http://wiki.jikexueyuan.com/project/servlet/auto-refresh.html：
假设一个Web页面，显示了现场比赛得分或股票市场状况或货币兑换率。对于所有这些类型的页面，都需要使用浏览器中的Refresh或Reload按钮来定期刷新Web页面。
Java Servlet提供一个机制使这项工作变得简单，可以使得Web页面在给定的时间间隔自动刷新。
刷新一个Web页面最简单的方式是使用响应对象的方法setIntHeader()。以下是这种方法的特征：
public void setIntHeader(String header, int headerValue)
此方法将头信息“Refresh”和一个表示时间间隔的整数值（以秒为单位）发送回浏览器。
一、自动刷新页面实例
这个例子演示了Servlet如何使用setIntHeader()方法设置Refresh头信息，实现自动刷新页面。
// Import required java libraries import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.util.*; // Extend HttpServlet class public class Refresh extends HttpServlet { // Method to handle GET method request. public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // Set refresh, autoload time as 5 seconds response.setIntHeader("Refresh", 5); // Set response content type response.setContentType("text/html"); // Get current time Calendar calendar = new GregorianCalendar(); String am_pm; int hour = calendar.get(Calendar.HOUR); int minute = calendar.get(Calendar.MINUTE); int second = calendar.get(Calendar.SECOND); if(calendar.get(Calendar.AM_PM) == 0) am_pm = "AM"; else am_pm = "PM"; String CT = hour+":"+ minute +":"+ second +" "+ am_pm; PrintWriter out = response.getWriter(); String title = "Auto Page Refresh using Servlet"; String docType = "<!doctype html public "-//w3c//dtd html 4.0 " + "transitional//en"> "; out.println(docType + "<html> " + "<head><title>" + title + "</title></head> "+ "<body bgcolor="#f0f0f0"> " + "<h1 align="center">" + title + "</h1> " + "<p>Current Time is: " + CT + "</p> "); } // Method to handle POST method request. public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
现在编译上述Servlet并在web.xml文件中创建以下条目：
.... <servlet> <servlet-name>Refresh</servlet-name> <servlet-class>Refresh</servlet-class> </servlet> <servlet-mapping> <servlet-name>Refresh</servlet-name> <url-pattern>/Refresh</url-pattern> </servlet-mapping> ....
现在使用URL http://localhost:8080/Refresh来调用这个Servlet。这将会每隔5秒钟显示一次当前系统时间，如下所示。运行该Servlet并等着看结果：
测试工程：https://github.com/easonjim/5_java_example/tree/master/servletbasics/test15