java project——CometSocket包含一个类:
Calculate.java:作为客户端,往服务器发送数据
web project——CometServer包含:
ReceiverServlet.java:接收客户端数据,并模拟入库(以存入文件的形式)
TestServlet.java:模拟从库中取数据(从文件中取值)并推送给浏览器展示
index.jsp:接收从服务端推送出来的数据并展示
2、部分代码说明
Calculate.java
public void sendData(ActionEvent e) { try { //发送数据 txtResult.setText(e.getActionCommand()); URL url = new URL("http://localhost:8080/CometServer/rs?num="+txtResult.getText()); HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection(); httpURLConnection.setRequestProperty("Content-Type", "text/html"); //application/xml httpURLConnection.setRequestMethod("GET"); httpURLConnection.setReadTimeout(2*1000); int code = httpURLConnection.getResponseCode(); System.out.println("code_______________"+code); }
通过http get请求方式将数据发送给客户端
ReceiverServlet.java
public void service(HttpServletRequest request ,HttpServletResponse response){ FileOutputStream fos = null; try { String str = request.getParameter("num"); System.out.println("get________________________________"+str); File file = new File("D:/1.txt"); fos = new FileOutputStream(file); if(str != null){ fos.write(str.getBytes()); } } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally{ if(fos != null){ try { fos.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } }
接收数据并模拟入库
TestServlet.java
public void event(CometEvent event) throws IOException, ServletException { // 开始 if(event.getEventType() == EventType.BEGIN){ try { Thread.sleep(100); File file = new File ("D:/1.txt"); BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file))); String str = br.readLine(); System.out.println("ddd1_________"+str); if( str != null){ HttpServletResponse response = event.getHttpServletResponse(); PrintWriter out = response.getWriter(); out.write(str); out.flush(); out.close(); } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } if(event.getEventType() == EventType.END){ System.out.println("ddd2"); event.close(); } }
定时向服务器推送数据
3、运行
tomcat配置: 要使用 Comet,需要对 Tomcat 的配置文件 server.xml 稍作修改。默认情况下启用的是更典型的同步 IO 连接器。现在只需将它切换成异步版本.
<!-- Connector URIEncoding="utf-8" connectionTimeout="20000" port="8080" protocol="HTTP/1.1" redirectPort="8443"/ -->
<Connector connectionTimeout="20000" port="8080" protocol="org.apache.
coyote.http11.Http11NioProtocol" redirectPort="8443"/>
源码和效果图,如附件:
启动web工程,点击“start”
运行Calculate.java