Question

我正在尝试按照this tutorial中的说明操作，并在Netbeans中创建一个示例应用程序。我已到达测试部分。当我在chrome中运行应用程序时，它说

WebSocket连接到＆＃39; WS：//本地主机：8080 / WhiteboardApp / whiteboardendpoint＆＃39;失败：错误在WebSocket握手期间：意外的响应代码：404

的index.html

<!DOCTYPE html>
<html>
    <head>
        <title>Start Page</title>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    </head>
    <body>
        <h1>Collaborative Whiteboard App</h1>
        <div id="output"></div>
        <script type="text/javascript" src="websocket.js"></script>
    </body>
</html>

websocket.js

var wsUri = "ws://" + document.location.host + document.location.pathname + "whiteboardendpoint";
var websocket = new WebSocket(wsUri);

websocket.onerror = function(evt) { onError(evt) };

function onError(evt) {
    writeToScreen('<span style="color: red;">ERROR:</span> ' + evt.data);
}

// For testing purposes
var output = document.getElementById("output");
websocket.onopen = function(evt) { onOpen(evt) };

function writeToScreen(message) {
    output.innerHTML += message + "<br>";
}

function onOpen(evt) {
    writeToScreen("Connected to " + wsUri);
}
// End test functions

MyWhiteboard.java

package org.myapps.whiteboardapp;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;

@ServerEndpoint("/whiteboardendpoint ")
public class MyWhiteboard {
    private static Set<Session> peers = Collections.synchronizedSet(new HashSet<Session>());

    @OnMessage
    public String onMessage(String message) {
        return null;
    }

    @OnOpen
    public void onOpen (Session peer) {
        peers.add(peer);
    }

    @OnClose
    public void onClose (Session peer) {
        peers.remove(peer);
    }
}

我哪里出错了？我该如何解决这个问题？

Answer 1

您的服务器注释无效

修复此问题

@ServerEndpoint("/whiteboardendpoint ")

要

@ServerEndpoint("/whiteboardendpoint") /* removed space */

您目前定义的方式，您可能只需将javascript wsUri定义更改为...

var wsUri = "ws://" + document.location.host + document.location.pathname +
            "whiteboardendpoint%20";
var websocket = new WebSocket(wsUri);

并让它工作。（只是添加了一个URI编码空间）

WebSocket握手期间出错

1 个答案: