java - Java 中的简单 Websocket 客户端 - 连接问题

Question

我正在尝试用 Java 编写一个简单的 websocket 客户端以连接到第 3 方 WebSocket 服务器(我无权访问该服务器)。

我可以在浏览器中使用 javascript 连接并与 websocket 服务器通信，但是当我尝试使用 Java 客户端做同样的事情时，它无法连接。

使用相同的 java 客户端，我可以连接到我正在运行的 tomcat websocket 服务器，所以我认为这是客户端和服务器之间的某种兼容性问题。 (我正在为 websocket 客户端使用 Tomcat 7.0.56 库)。

这是我得到的错误...

错误

javax.websocket.DeploymentException: The HTTP request to initiate the WebSocket connection failed
    at org.apache.tomcat.websocket.WsWebSocketContainer.connectToServer(WsWebSocketContainer.java:344)
    at org.apache.tomcat.websocket.WsWebSocketContainer.connectToServer(WsWebSocketContainer.java:166)
    at com.cvr.instant.ws.WebSocketClient.Connect(WebSocketClient.java:44)
    at com.cvr.instant.ws.TestWS.Start(TestWS.java:17)
    at com.cvr.instant.ws.TestWS.main(TestWS.java:37)
Caused by: java.io.EOFException
    at org.apache.tomcat.websocket.WsWebSocketContainer.processResponse(WsWebSocketContainer.java:595)
    at org.apache.tomcat.websocket.WsWebSocketContainer.connectToServer(WsWebSocketContainer.java:317)
... 4 more

WebSocketClient

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;

import javax.websocket.ClientEndpoint;
import javax.websocket.CloseReason;
import javax.websocket.ContainerProvider;
import javax.websocket.DeploymentException;
import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.WebSocketContainer;

@ClientEndpoint
public class WebSocketClient {

    protected   WebSocketContainer container;
    protected   Session userSession = null;

    public WebSocketClient() {
        container = ContainerProvider.getWebSocketContainer();
    }

    public void Connect(String sServer) {

          try {
              userSession = container.connectToServer(this, new URI(sServer));

            } catch (DeploymentException | URISyntaxException | IOException e) {
                e.printStackTrace();
            }

    }

    public void SendMessage(String sMsg) throws IOException {
        userSession.getBasicRemote().sendText(sMsg);
    }

    @OnOpen
    public void onOpen(Session session) {
        System.out.println("Connected");
    }

    @OnClose
    public void onClose(Session session, CloseReason closeReason) {
    }

    @OnMessage
    public void onMessage(Session session, String msg) {
        System.out.println(msg);
    }

    public void Disconnect() throws IOException {
        userSession.close();
    }
}

运行客户端

import java.io.IOException;

public class TestWS {

    public WebSocketClient wsc;
    public TestWS() {
    }

    public void Start() throws InterruptedException, IOException {

        wsc = new WebSocketClient();
        wsc.callback = this;
        wsc.Connect("ws://192.168.0.25:9000");
        Thread.sleep(1000);
        wsc.Disconnect();
    }


    public static void main(String[] args) throws InterruptedException, IOException 
    {
        TestWS t = new TestWS();
        t.Start();
        Thread.sleep(1000);
    }

}    

我对 websocket 客户端非常陌生(一般来说对 websockets 相当陌生)。如果您能提供任何帮助，我们将不胜感激!

Answer 1

我发现了问题 - 当从 Java 客户端运行时，ws 地址需要在其末尾添加一个“/”。

JavaScript ws://192.168.0.25:9000

Java ws://192.168.0.25:9000/

不确定为什么这在 Java 中是必需的 - 但它解决了问题......