WebSocket集成XMPP网页即时通讯3：二进制文件收发

WebSocket支持二进制的发送，见jetty官网：

http://www.eclipse.org/jetty/documentation/current/jetty-websocket-api-send-message.html

Blocking Send Message 阻塞式

Most calls are blocking in nature, and will not return until the send has completed (or has thrown an exception).

RemoteEndpoint remote = session.getRemote();

// Blocking Send of a BINARY message to remote endpoint
ByteBuffer buf = ByteBuffer.wrap(new byte[] { 0x11, 0x22, 0x33, 0x44 });
try
{
    remote.sendBytes(buf);
}
catch (IOException e)
{
    e.printStackTrace(System.err);
}

Send Partial Message 分块式

RemoteEndpoint remote = session.getRemote();

// Blocking Send of a BINARY message to remote endpoint
// Part 1
ByteBuffer buf1 = ByteBuffer.wrap(new byte[] { 0x11, 0x22 });
// Part 2 (last part)
ByteBuffer buf2 = ByteBuffer.wrap(new byte[] { 0x33, 0x44 });
try
{
    remote.sendPartialBytes(buf1,false);
    remote.sendPartialBytes(buf2,true); // isLast is true
}
catch (IOException e)
{
    e.printStackTrace(System.err);
}

Async Send Message 异步

 //Example 29.7. Send Binary Message (Async Simple)

RemoteEndpoint remote = session.getRemote();

// Async Send of a BINARY message to remote endpoint
ByteBuffer buf = ByteBuffer.wrap(new byte[] { 0x11, 0x22, 0x33, 0x44 });
remote.sendBytesByFuture(buf);

// Example 29.8. Send Binary Message (Async, Wait Till Success)

RemoteEndpoint remote = session.getRemote();

// Async Send of a BINARY message to remote endpoint
ByteBuffer buf = ByteBuffer.wrap(new byte[] { 0x11, 0x22, 0x33, 0x44 });
try
{
    Future<Void> fut = remote.sendBytesByFuture(buf);
    // wait for completion (forever)
    fut.get();
}
catch (ExecutionException | InterruptedException e)
{
    // Send failed
    e.printStackTrace();
}

How to send a simple Binary message using the RemoteEndpoint, tracking the Future<Void> to know if the send succeeded or failed.

//Example 29.9. Send Binary Message (Async, timeout of send)

RemoteEndpoint remote = session.getRemote();

// Async Send of a BINARY message to remote endpoint
ByteBuffer buf = ByteBuffer.wrap(new byte[] { 0x11, 0x22, 0x33, 0x44 });
Future<Void> fut = null;
try
{
    fut = remote.sendBytesByFuture(buf);
    // wait for completion (timeout)
    fut.get(2,TimeUnit.SECONDS);
}
catch (ExecutionException | InterruptedException e)
{
    // Send failed
    e.printStackTrace();
}
catch (TimeoutException e)
{
    // timeout
    e.printStackTrace();
    if (fut != null)
    {
        // cancel the message
        fut.cancel(true);
    }
}