问题
I have one SockJS Java client that use STOMP. Is base on this https://github.com/rstoyanchev/spring-websocket-portfolio/blob/master/src/test/java/org/springframework/samples/portfolio/web/load/StompWebSocketLoadTestClient.java.
My code:
package mx.intercommunication.websocket.stompclient;
import org.springframework.messaging.converter.StringMessageConverter;
import org.springframework.messaging.simp.stomp.StompCommand;
import org.springframework.messaging.simp.stomp.StompHeaders;
import org.springframework.messaging.simp.stomp.StompSession;
import org.springframework.messaging.simp.stomp.StompSessionHandlerAdapter;
import org.springframework.web.socket.client.WebSocketClient;
import org.springframework.web.socket.client.standard.StandardWebSocketClient;
import org.springframework.web.socket.sockjs.client.SockJsClient;
import org.springframework.web.socket.sockjs.client.Transport;
import org.springframework.web.socket.sockjs.client.WebSocketTransport;
public class StompClient {
public StompClient(){
cliente();
}
public void cliente() {
String host = "localhost";
int port = 8080;
String stompUrl = "ws://{host}:{port}/Server/chat";
StandardWebSocketClient webSocketClient = new StandardWebSocketClient();
List<Transport> transports = new ArrayList<>(2);
/*
* The WebSocketTransport can be configured with:
* + StandardWebSocketClient in a JSR-356 runtime
* + JettyWebSocketClient using the Jetty 9+ native WebSocket API
* + Any implementation of Spring’s WebSocketClient
*/
transports.add(new WebSocketTransport(webSocketClient));
SockJsClient sockJsClient = new SockJsClient(transports);
WebSocketStompClient stompClient = new WebSocketStompClient(sockJsClient);
//Configure a scheduler to use for heartbeats and for receipt tracking.
//stompClient.setTaskScheduler(taskScheduler);
//stompClient.setDefaultHeartbeat(new long[] {0, 0});
/*
* Set the MessageConverter to use to convert the payload of incoming and
* outgoing messages to and from byte[] based on object type and the "content-type" header.
* By default, SimpleMessageConverter is configured.
*/
stompClient.setMessageConverter(new StringMessageConverter());
ProducerStompSessionHandler producer = new ProducerStompSessionHandler();
/*
* Connect to the given WebSocket URL and notify the given
* org.springframework.messaging.simp.stomp.StompSessionHandler when connected on
* the STOMP level after the CONNECTED frame is received.
*
* Parameters:
* url the url to connect to
* handler the session handler
* uriVars URI variables to expand into the URL
* Returns:
* ListenableFuture for access to the session when ready for use
*
*/
stompClient.connect(stompUrl, producer, host, port);
}
private static class ProducerStompSessionHandler extends StompSessionHandlerAdapter {
//private final AtomicReference<Throwable> failure;
private StompSession session;
@Override
public void afterConnected(StompSession session, StompHeaders connectedHeaders) {
this.session = session;
try {
Thread.sleep(6000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Json m = Json.object()
.set("from", "cliente1")
.set("text", "KIKO");
String message = m.toString();
//byte messageByteArr[] = message.getBytes();
/*
* Send a message to the specified destination, converting the payload to a
* byte[] with the help of a MessageConverter.
*
* Parameters:
* destination: the destination to send a message to
* payload: the message payload
* Returns:
* a Receiptable for tracking receipts
*/
try {
session.send("/app/chatchannel", message);
//session.send("/app/chatchannel", messageByteArr);
System.out.println("Sending message HELLO: "+message);
} catch (Throwable t) {
System.out.println("Message sending failed: "+t);
//logger.error("Message sending failed at " + i, t);
//failure.set(t);
}
}
/**
* This implementation returns String as the expected payload type
* for STOMP ERROR frames.
*/
@Override
public Type getPayloadType(StompHeaders headers) {
return String.class;
}
@Override
public void handleFrame(StompHeaders headers, Object payload) {
Exception ex = new Exception(headers.toString());
System.out.println("STOMP ERROR frame: "+ex);
}
@Override
public void handleException(StompSession session, StompCommand command, StompHeaders headers,
byte[] payload, Throwable exception) {
System.out.println("Handling exception: "+exception);
}
@Override
public void handleTransportError(StompSession session, Throwable exception) {
System.out.println("Transport error: "+exception);
}
@Override
public String toString() {
//return "ConsumerStompSessionHandler[messageCount=" + this.messageCount + "]";
return "ConsumerStompSessionHandler to String....";
}
}
}
Please check that when I configure stompClient as:
stompClient.setMessageConverter(new StringMessageConverter());
and I send a message:
session.send("/app/chatchannel", message);
where message is a String class object, the server side thrown the next conversion error:
08:51:06,746 ERROR [org.springframework.web.socket.messaging.WebSocketAnnotationMethodMessageHandler] (clientInboundChannel-4) Unhandled exception from message handler method: org.springframework.messaging.converter.MessageConversionException: Cannot convert from [[B] to [org.gasmart.websocket.Message] for GenericMessage [payload=byte[33], headers={simpMessageType=MESSAGE, stompCommand=SEND, nativeHeaders={destination=[/app/chatchannel], content-type=[text/plain;charset=UTF-8], content-length=[33]}, simpSessionAttributes={ip=/127.0.0.1:59629}, simpHeartbeat=[J@147a2bf, contentType=text/plain;charset=UTF-8, lookupDestination=/chatchannel, simpSessionId=79431feb8b5f4a9497492ccc64f8965f, simpDestination=/app/chatchannel}]
at org.springframework.messaging.handler.annotation.support.PayloadArgumentResolver.resolveArgument(PayloadArgumentResolver.java:124)
at org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:112)
at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:138)
at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:107)
at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMatch(AbstractMethodMessageHandler.java:502)
at org.springframework.messaging.simp.annotation.support.SimpAnnotationMethodMessageHandler.handleMatch(SimpAnnotationMethodMessageHandler.java:497)
at org.springframework.messaging.simp.annotation.support.SimpAnnotationMethodMessageHandler.handleMatch(SimpAnnotationMethodMessageHandler.java:87)
at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMessageInternal(AbstractMethodMessageHandler.java:461)
at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMessage(AbstractMethodMessageHandler.java:399)
at org.springframework.messaging.support.ExecutorSubscribableChannel$SendTask.run(ExecutorSubscribableChannel.java:135)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Observe the error:
MessageConversionException: Cannot convert from [[B] to [org.gasmart.websocket.Message] for GenericMessage [payload=byte[33], headers={simpMessageType=MESSAGE, stompCommand=SEND, nativeHeaders={destination=[/app/chatchannel], content-type=[text/plain;charset=UTF-8], content-length=[33]}, simpSessionAttributes={ip=/127.0.0.1:59629}, simpHeartbeat=[J@147a2bf, contentType=text/plain;charset=UTF-8, lookupDestination=/chatchannel, simpSessionId=79431feb8b5f4a9497492ccc64f8965f, simpDestination=/app/chatchannel}]
see that the content-type header is created by the SockJS Java client.
If I configure stompClient as:
stompClient.setMessageConverter(new SimpleMessageConverter());
and I send a message:
...
String message = m.toString();
byte messageByteArr[] = message.getBytes();
session.send("/app/chatchannel", message);
where message is a byte array , the server don't thrown error. But I need to be converting all the String to byte array before to send. I want understand why the Server can convert the same JSON object send with a SimpleMessageConverter and one send with StringMessageConverter.
I do a comparative of a JSON sended from a JavaScript client and the Java client. Both send the same JSON message. Then I implemented a ChannelInterceptor to print the messages received before the message to be send to the corresponding controller:
public class WebSocketTraceChannelInterceptor extends ChannelInterceptorAdapter {
@Override
public void afterSendCompletion(Message<?> message, MessageChannel channel, boolean sent, Exception ex) {
String payload = new String((byte[]) message.getPayload());
System.out.println("WebSocketTraceChannelInterceptor::afterSendCompletion!! payload: "+payload);
}
}
The corresponding server controller is:
@MessageMapping("/chatchannel")
@SendTo("/topic/messages")
public OutputMessage send(SimpMessageHeaderAccessor ha,@Payload Message message) throws Exception {
.....
}
The Java output:
message: GenericMessage [payload=byte[33], headers={simpMessageType=MESSAGE, stompCommand=SEND, nativeHeaders={destination=[/app/chatchannel], **content-type=[text/plain;charset=UTF-8]**, content-length=[33]}, simpSessionAttributes={ip=/127.0.0.1:59629}, simpHeartbeat=[J@147a2bf, contentType=text/plain;charset=UTF-8, simpSessionId=79431feb8b5f4a9497492ccc64f8965f, simpDestination=/app/chatchannel}]
while the JavaScript: SockJS + Stomp.js:
message: GenericMessage [payload=byte[33], headers={simpMessageType=MESSAGE, stompCommand=SEND, nativeHeaders={destination=[/app/chatchannel], content-length=[33]}, simpSessionAttributes={ip=/127.0.0.1:57890}, simpHeartbeat=[J@d154f0, simpSessionId=innyvfme, simpDestination=/app/chatchannel}]
Observe the difference: content-type=[text/plain;charset=UTF-8]
There are more converters in Spring messaging:
You can observe the SimpleMessageConverter and the StringMessageConverter in this package. But there are ByteArrayMessageConverter, CompositeMessageConverter, SmartMessageConverter, etc. How work this converters?
If I want sent String from the Java Client what converter I need ?
Why the server can convert the JSON message {"from":"cliente1","text":"KIKO"} when is send from a JScript client but not whe send form the Java client?
回答1:
try to create a Bean like
public class SimpleBean{
private String from;
private String text;
public String getFrom(){return from;}
public String getText(){return text:}
//other methods like setters here...
}
then set the messageConverter in this way
MappingJackson2MessageConverter m = new MappingJackson2MessageConverter();
stompClient.setMessageConverter(m);
I have not seen any invocation of the "subscribe" method for your client in the method "afterConnected(StompSession session, StompHeaders connectedHeaders)"
session.subscribe(subscribeMethod, new StompFrameHandler() {
//.. overriding for public Type getPayloadType(StompHeaders headers) {} and
// public void handleFrame(StompHeaders headers, Object payload) {} here
});
Than call for the "send" method, using an instance for the SimpleBean defined just before:
SimpleBean sb=new SimpleBean();
sb.setFrom("cliente1");
sb.setText("KIKO");
session.send("/app/chatchannel", sb);
This should help.
来源：https://stackoverflow.com/questions/39024998/how-configure-the-spring-sockjs-java-client-message-converters