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Version: 9.3.10.v20160621
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Jetty WebSocket Client API

The WebSocketClient

Jetty also provides a Jetty WebSocket Client Library to write make talking to WebSocket servers easier.

To use the Jetty WebSocket Client on your own Java project you will need the following maven artifacts.

<dependency>
  <groupId>org.eclipse.jetty.websocket</groupId>
  <artifactId>websocket-client</artifactId>
  <version>${project.version}</version>
</dependency>

The WebSocketClient

To use the WebSocketClient you will need to hook up a WebSocket object instance to a specific destination WebSocket URI.

//
//  ========================================================================
//  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package examples;

import java.net.URI;
import java.util.concurrent.TimeUnit;

import org.eclipse.jetty.websocket.client.ClientUpgradeRequest;
import org.eclipse.jetty.websocket.client.WebSocketClient;

/**
 * Example of a simple Echo Client.
 */
public class SimpleEchoClient
{
    public static void main(String[] args)
    {
        String destUri = "ws://echo.websocket.org";
        if (args.length > 0)
        {
            destUri = args[0];
        }

        WebSocketClient client = new WebSocketClient();
        SimpleEchoSocket socket = new SimpleEchoSocket();
        try
        {
            client.start();

            URI echoUri = new URI(destUri);
            ClientUpgradeRequest request = new ClientUpgradeRequest();
            client.connect(socket,echoUri,request);
            System.out.printf("Connecting to : %s%n",echoUri);

            // wait for closed socket connection.
            socket.awaitClose(5,TimeUnit.SECONDS);
        }
        catch (Throwable t)
        {
            t.printStackTrace();
        }
        finally
        {
            try
            {
                client.stop();
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
        }
    }
}

The above example connects to a remote WebSocket server and hands off a SimpleEchoSocket to perform the logic on the websocket once connected, waiting for the socket to register that it has closed.

//
//  ========================================================================
//  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package examples;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

import org.eclipse.jetty.websocket.api.Session;
import org.eclipse.jetty.websocket.api.StatusCode;
import org.eclipse.jetty.websocket.api.annotations.OnWebSocketClose;
import org.eclipse.jetty.websocket.api.annotations.OnWebSocketConnect;
import org.eclipse.jetty.websocket.api.annotations.OnWebSocketMessage;
import org.eclipse.jetty.websocket.api.annotations.WebSocket;

/**
 * Basic Echo Client Socket
 */
@WebSocket(maxTextMessageSize = 64 * 1024)
public class SimpleEchoSocket
{
    private final CountDownLatch closeLatch;
    @SuppressWarnings("unused")
    private Session session;

    public SimpleEchoSocket()
    {
        this.closeLatch = new CountDownLatch(1);
    }

    public boolean awaitClose(int duration, TimeUnit unit) throws InterruptedException
    {
        return this.closeLatch.await(duration,unit);
    }

    @OnWebSocketClose
    public void onClose(int statusCode, String reason)
    {
        System.out.printf("Connection closed: %d - %s%n",statusCode,reason);
        this.session = null;
        this.closeLatch.countDown(); // trigger latch
    }

    @OnWebSocketConnect
    public void onConnect(Session session)
    {
        System.out.printf("Got connect: %s%n",session);
        this.session = session;
        try
        {
            Future<Void> fut;
            fut = session.getRemote().sendStringByFuture("Hello");
            fut.get(2,TimeUnit.SECONDS); // wait for send to complete.

            fut = session.getRemote().sendStringByFuture("Thanks for the conversation.");
            fut.get(2,TimeUnit.SECONDS); // wait for send to complete.

            session.close(StatusCode.NORMAL,"I'm done");
        }
        catch (Throwable t)
        {
            t.printStackTrace();
        }
    }

    @OnWebSocketMessage
    public void onMessage(String msg)
    {
        System.out.printf("Got msg: %s%n",msg);
    }
}

When the SimpleEchoSocket connects, it sends 2 Text messages and then closes the socket.

The onMessage(String msg) receives the responses from the remote server WebSocket and outputs them to the console.

See an error or something missing? Contribute to this documentation at Github!(Generated: 2016-06-21)