Question

根据（Is it possible to send binary data with STOMP over WebSockets using Spring-WebSockets?），似乎应该可以通过websockets发送带有STOMP的二进制消息。

我已按如下方式配置了WebSocketStompClient：

List<Transport> transports = new ArrayList<>(1);
transports.add(new WebSocketTransport( new StandardWebSocketClient()) );
WebSocketClient transport = new SockJsClient(transports);
WebSocketStompClient stompClient = new WebSocketStompClient(transport);
// using a custom converter to serialize java object to byte[]
stompClient.setMessageConverter( new SerializedJavaObjectMessageConverter() );

我使用以下内容发送消息：

StompHeaders stompHeaders = new StompHeaders();
stompHeaders.setDestination( "/app/greetings");
stompHeaders.setContentType( MimeTypeUtils.APPLICATION_OCTET_STREAM );
session.send(stompHeaders, new Greeting( message ));

我从以下断言中收到一个例外：

Assert.isInstanceOf(TextMessage.class, message, this + " supports text messages only.");

在org.springframework.web.socket.sockjs.client.AbstractClientSockJs（下面）中找到，它似乎只支持TextMessage：

@Override
public final void sendMessage(WebSocketMessage<?> message) throws IOException {
    Assert.state(State.OPEN.equals(this.state), this + " is not open, current state=" + this.state);
    Assert.isInstanceOf(TextMessage.class, message, this + " supports text messages only.");
    String payload = ((TextMessage) message).getPayload();
    payload = getMessageCodec().encode(new String[] { payload });
    payload = payload.substring(1); // the client-side doesn't need message framing (letter "a")
    message = new TextMessage(payload);
    if (logger.isTraceEnabled()) {
            logger.trace("Sending message " + message + " in " + this);
    }
    sendInternal((TextMessage) message);
}

上面配置的新的Java客户端WebSocketStompClient（4.2-SNAPSHOT）（即使用SockJS进行回退）是否支持发送二进制消息？

更新

以下客户端配置有效：

WebSocketClient transport = new StandardWebSocketClient();
WebSocketStompClient stompClient = new WebSocketStompClient(transport)

Answer 1

我能够通过发送TextMessage来实现这一点。我创建了另一个自定义MessageConverter，Base64对序列化对象进行编码/解码：

public class Base64JavaObjectMessageConverter extends AbstractMessageConverter {

    public Base64JavaObjectMessageConverter() {
        super(MimeTypeUtils.TEXT_PLAIN);
    }

    @Override
    protected boolean supports(Class<?> clazz) {
        return true;
    }

    @Override
    public Object convertFromInternal(Message<?> message, Class<?> targetClass) {
        byte[] messageBytes = Base64.getDecoder().decode( (byte[])message.getPayload() );
        return SerializationUtils.deserialize( messageBytes  );
    }

    @Override
    public Object convertToInternal(Object payload, MessageHeaders headers) {
        byte[] messageBytes = SerializationUtils.serialize( payload );
        return Base64.getEncoder().encode( messageBytes);
    }

}

从java WebSocketStompClient

1 个答案: