【转】轮询、长轮询、iframe长连接、web socket

时间：2022-12-06 22:48:27

引自：http://www.cnblogs.com/AloneSword/p/3517463.html

http://www.cnblogs.com/wei2yi/archive/2011/03/23/1992830.html

代码示例：

1.iframe实现长连接

<%@ page language="java" contentType="text/html; charset=GB18030"

    pageEncoding="GB18030"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=GB18030">

<title>Insert title here</title>

</head>

<script type="text/javascript" src="jquery-1.9.1.js"></script>

<script>

    function loadData(){

        $('#logs').append(new Date());

    }

</script>

<body>

<iframe id="frame" name="polling" src="/myweb/TestLongPolling"></iframe>

        <div id="logs"></div>

</body>

</html>
package bookstore;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/**

 * Servlet implementation class TestLongPolling

 */

@WebServlet("/TestLongPolling")

public class TestLongPolling extends HttpServlet {

    private static final long serialVersionUID = 1L;

    /**

     * @see HttpServlet#HttpServlet()

     */

    public TestLongPolling() {

        super();

        // TODO Auto-generated constructor stub

    }

    /**

     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

     */

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        // TODO Auto-generated method stub

        doPost(request,response);

    }

    /**

     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)

     */

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        // TODO Auto-generated method stub

        int i = 0;

        boolean boo = true;

        String result = null;

        while(boo){

            try {

                    Thread.sleep(1000);

                } catch (InterruptedException e) {

                    e.printStackTrace();

                }

            result = "hello I'm server"+i;//要打印到前台的字符

            //sendMsg(result,response,"msg");//msg是test.jsp中的那个js方法的名称  

                response.setContentType("text/html;charset=GBK");

                response.getWriter().write(

                        "<script type='text/javascript'>parent.loadData()</script>");

                response.flushBuffer();  

            i++;

            if(i==10){

                boo = false;

            }

        }

    }

}

2.web socket

待续....

相关文章