服务器推送技术总结

来源：互联网发布：小米抢红包软件编辑：程序博客网时间：2024/05/18 03:44
废话不多说，直接上代码！一、ajax轮询太过简单，这里不做介绍；--------------------二、ajax长轮询(servlet3.0才能使用)如下:----------------------------1、前端代码（递归调用）：<script type="text/javascript">     longloop();     function longloop(){         $.get("ontimeNews",function (data) {             console.log(data);             $("#onTimeNews").html(data);             longloop();         })     } </script>2、后台（采用spring提供的API）： @Controllerpublic class NewsController {    private DeferredResult<String> deferredResult ;    private Random r = new Random();    @RequestMapping("/news")    public String news(){        return "news";    }    @RequestMapping(value="/ontimeNews",produces = "text/html;charset=UTF-8")    @ResponseBody    public DeferredResult<String> ontimeNews(){        deferredResult = new DeferredResult<String>();        return deferredResult;    }    @Scheduled(fixedDelay = 5000)    public void refresh(){        if (deferredResult!=null){            int index = r.nextInt(Const.NEWS.length);           deferredResult.setResult(Const.NEWS[index]);        }    }}三、comet流方式（http长连接方式）：----------------------1、前端代码： <%@ page language = "java" contentType= "text/html; charset=UTF-8" pageEncoding= "UTF-8" %><!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=UTF-8"><title>股票实时行情</title></head><body><h1>股票实时行情</h1><div>    <div>        <h2>(流方式)股票列表</h2>    </div>    <div>        <h2 id="hint"></h2>    </div>    <hr>    <div>        <div><p>Java公司</p><p id="c0" style="color:#F00"></p><b><p id="s0">历史股价：</p></b></div>        <div><p>C/C++公司</p><p id="c1" style="color:#F00"></p><b><p id="s1">历史股价：</p></b></div>        <div><p>PHP公司</p><p id="c2" style="color:#F00"></p><b><p id="s2">历史股价：</p></b></div>        <div><p>Python公司</p><p id="c3" style="color:#F00"></p><b><p id="s3">历史股价：</p></b></div>    </div>    <hr></div><script type="text/javascript" src="assets/js/jquery-1.9.1.min.js"></script><script type="text/javascript">    if (!!window.EventSource){        var source = new EventSource("stockOnTime");        source.onmessage=function (e) {            var dataObj = e.data;            console.log(dataObj);            var arr = dataObj.split(",");            $.each(arr,function (i,item) {                $("#c"+i).html("股价："+item);                var s = $("#s"+i).html();                $("#s"+i).html(s+item+"  ");            });            $("#hint").html("");        };        source.onopen=function (e) {            console.log("Conecting ....");        };        source.onerror=function () {            console.log("error ....");        };    }else{        $("#hint").html("Not support sse");    }</script></body></html>2、后台： @Controllerpublic class StockController {    @RequestMapping("/stock")    public String news(){        return "stock";    }    @RequestMapping(value="/stockOnTime",produces = "text/event-stream;charset=UTF-8")    @ResponseBody    public String push(){        Random r = new Random();        try {            Thread.sleep(500);        } catch (InterruptedException e) {            e.printStackTrace();        }        StringBuilder sb = new StringBuilder("");        sb.append("retry:2000\n")                .append("data:")                .append((r.nextInt(100)+50)+",")                .append((r.nextInt(80)+45)+",")                .append((r.nextInt(60)+40)+",")                .append((r.nextInt(40)+35)+",")                .append("\n\n");        return sb.toString();    }}
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