Question

我一直在本地测试WebSockets和$.post()之间的区别，并且发现$ .post（）在以下情况下比WebSockets一样强<76> ：

方案

客户端向服务器发布命令（＆＃34; start＆＃34;）。
服务器以命令响应（＆＃34;准备就绪＆＃34;）。
客户将命令（＆＃34;文件＆＃34;）发布到服务器。
服务器响应包含单词＆＃34; Lorem＆＃34;的1.4MB（大约）文本文件的内容。
客户端收到此文件并重复循环10次。

客户AJAX $ .post（）：

httpPost('start', 0);
function httpPost(cmd, iteration) {
    $.post('http://path/to/server', {cmd:cmd}, function(data){
        switch(data) {
        case "ready":
            // request file
            httpPost('file', iteration);
            break;
        case "received":
            if(iteration == 9) {
                // total time taken is recorded here (omitted)
            }else{      
                httpPost('start', ++iteration);
                break;
            }
        }

        if(data.indexOf('Lorem') > -1) {
            // acknowledge receipt of file
            httpPost('Lorem', iteration);
        }

    });
}

Server PostController：

@WebServlet("/post")
public class PostController extends HttpServlet{

    private static final long serialVersionUID = 1L;

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String cmd = req.getParameter("cmd");

        PrintWriter out = resp.getWriter();
        if(cmd != null) {
            switch(cmd) {
            case "start":
                out.append("ready");
                break;
            case "file":
                String absoluteDiskPath = getServletContext().getRealPath("/resources/file.txt");
                String contents = FileUtils.readFileToString(new File(absoluteDiskPath));
                out.append(contents);
                break;
            case "concurrency":
                out.append("concurrency");
                break;
            case "Lorem":
                out.append("received");
                break;
            }
        }
        out.close();
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }
}

客户WebSockets API：

startWebSocket(); // open a single websocket connection and request a file 10 times
function startWebSocket() {
    var url = "ws://path/to/server";
    var socket = new WebSocket(url);
    var iteration = 0;

    socket.onmessage = function (event) {
         if (event.data.indexOf('ready') > -1) {
             // request file
             socket.send('file');
         }

         if(event.data.indexOf('Lorem') > -1) {
            // acknowledge receipt of file
            socket.send('Lorem');
         }

         if(event.data.indexOf('received') > -1) {
            if(iteration == 9) {
              // total time taken is recorded here (omitted)
            }else{          
                socket.send('start');
                iteration++;
            }
         }
     }

     socket.onopen = function (event) {
     };

     socket.onclose = function (event) {
     };

     socket.onerror = function (event) {
     };
}

服务器ServerEndPoint：

@ServerEndpoint(value = "/server")
public class Server{

    private static ArrayList<Session> sessionList = new ArrayList<Session>();

    @OnError
    public void onError(Session session, Throwable t) {
        sessionList.remove(session);
    }

    @OnOpen
    public void onOpen(Session session) {
        try {
            sessionList.add(session);
            session.getBasicRemote().sendText("ready");

        } catch (IOException e) {
        }
    }

    @OnClose
    public void onClose(Session session) {
        sessionList.remove(session);
    }

    @OnMessage
    public void onMessage(String msg) throws JSONException {

        String output = "";
        if(msg.equals("file")) {

            try {
                URL resource = getClass().getResource("/");
                String path = resource.getPath();
                String absoluteDiskPath = path + "../../resources/file.txt";
                output = FileUtils.readFileToString(new File(absoluteDiskPath));
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        if(msg.equals("Lorem")) {
            output = "received";
        }

        if(msg.equals("start")) {
            output = "ready";
        }

        for (int i = 0, size = sessionList.size(); i < size; i++) {
            try {
                sessionList.get(i).getBasicRemote().sendText(output);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

使用JQuery的$ .post（）和JavaScripts Websocket API在本地完成此测试。服务器是用Java编写的。

在最后一次测试中，AJAX $ .post（）方法在 0.450 秒内完成了10次调用，而10次Websocket API调用在 1.877 秒内完成。

我原本希望10个websocket调用能够以最快的速度完成，因为每条消息都会发送较少的标题。

那么，为什么JQuery的$ .post（）比WebSockets更快？

为什么WebSockets比AJAX $ .post（）慢？

0 个答案: