标签:tps 按钮 end enter oid lan 显示 机制 logs
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\">\n"; out.println(docType + "<html>\n" + "<head><title>" + title + "</title></head>\n"+ "<body bgcolor=\"#f0f0f0\">\n" + "<h1 align=\"center\">" + title + "</h1>\n" + "<p>Current Time is: " + CT + "</p>\n"); } // 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
标签:tps 按钮 end enter oid lan 显示 机制 logs
原文地址:http://www.cnblogs.com/EasonJim/p/6982998.html