標籤：
需求：
每當資料庫有資料更新時，推送到用戶端
軟需求：
1、伺服器資源有限，要求資源佔用儘可能小；
2、項目可控，不許調用第三方不可信不穩定的方法。
已有案例：
1、58到家採用的方法是TCP的長串連，對伺服器壓力較大；
2、redis等提供了訂閱推送服務，開源，但是定製化對開發人員其開發語言水平要求較高，筆者水平達不到
最終方案：
解釋：
①②頁面載入時第一次請求資料，返回資料，載入，調用ajax2
③頁面載入即發出請求，但是此時沒有資料，於是就block，等待其他組件insert msg
④收取新msg後，傳回值給ajax2
⑤ajax2調用ajax1
⑥ajax1重新整理資料
block後ajax2隻在伺服器佔用一個線程，資源消耗很小。
===================下面是代碼=======================
1、檔案結構
2、receive.cs//MSMQ的接收類
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Messaging;namespace WebApplication1{ public class receive { public String receives() { var queue = new MessageQueue(@".\private$\MsgQueue"); queue.Formatter = new XmlMessageFormatter( new string[] { "System.String" } ); Message m = queue.Receive(); return m.Body.ToString(); } }}
2、send.cs//MSMQ的發送類
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Messaging;namespace WebApplication1{ public class send { public string create(String msg) { try { if (!MessageQueue.Exists(@".\private$\MsgQueue")) { MessageQueue.Create(@".\private$\MsgQueue"); } var queue = new MessageQueue(@".\private$\MsgQueue"); queue.Send(msg, "Label"); return "ok"; } catch (Exception ex) { return "error"; } } }}
3、MQGiver.asmx//核心WebService
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.Services;using WebApplication1;namespace 伺服器接收mq{ /// <summary> /// MQGiver 的摘要說明 /// </summary> [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] [System.ComponentModel.ToolboxItem(false)] // 若要允許使用 ASP.NET AJAX 從指令碼中調用此 Web 服務，請取消對下行的注釋。 // [System.Web.Script.Services.ScriptService] [Serializable] public class MQGiver : System.Web.Services.WebService { [WebMethod] public string HelloWorld() { return "Hello World"; } [WebMethod] public void GiveMsg() { receive r = new receive(); String msg = r.receives(); String Json = "{\"msg\":\"" + msg + "\"}"; string callback = HttpContext.Current.Request["jsoncallback"]; HttpContext.Current.Response.Write(callback + "(" + Json + ")"); } [WebMethod] public void GiveData() { String Json = "{\"msg\":\"ok\"}"; string callback = HttpContext.Current.Request["jsoncallback"]; HttpContext.Current.Response.Write(callback + "(" + Json + ")"); } }}
4、MSGadd.aspx//類比向MSMQ添加資料
前台代碼<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="MSGadd.aspx.cs" Inherits="伺服器接收mq.MSGadd" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div> </div> <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" /> <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label> </form></body></html>//================================================後台代碼using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using WebApplication1;namespace 伺服器接收mq{ public partial class MSGadd : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void Button1_Click(object sender, EventArgs e) { send s = new send(); Label1.Text = s.create(TextBox1.Text); } }}
5、調用介面
<html><head> <!--自己注意jq包的引用--> <script src="jq.js"></script></head><body> <script type="text/javascript"> function getdata(){ $.ajax({ url: "http://localhost:55843/MQGiver.asmx/GiveData?jsoncallback=?", dataType: "jsonp", success: OnSuccess, }); function OnSuccess(json) { $("#la").text(json.msg) getmsg(); } } function getmsg(){ $.ajax({ url: "http://localhost:55843/MQGiver.asmx/GiveMsg?jsoncallback=?", dataType: "jsonp", success: OnSuccess1, }); function OnSuccess1(json1) { getdata(); } } getdata(); </script> <label id="la"> </label></body></html>
整個項目就是這樣的，已通，有好的建議和問題歡迎留言！
利用Ajax+MSMQ(訊息佇列)+WebService實現伺服器端向用戶端的資訊推送
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