注释类型 MessageMapping

@Target({TYPE,METHOD})
@Retention(RUNTIME)
@Documented
public @interface MessageMapping

Annotation for mapping a Message onto a message-handling method by matching the declared patterns to a destination extracted from the message. The annotation is supported at the type-level too, as a way of declaring a pattern prefix (or prefixes) across all class methods.

@MessageMapping methods support the following arguments:

• @Payload method argument to extract the payload of a message and have it de-serialized to the declared target type. @Payload arguments may also be annotated with Validation annotations such as @Validated and will then have JSR-303 validation applied. Keep in mind the annotation is not required to be present as it is assumed by default for arguments not handled otherwise.
• @DestinationVariable method argument for access to template variable values extracted from the message destination, e.g. /hotels/{hotel}. Variable values may also be converted from String to the declared method argument type, if needed.
• @Header method argument to extract a specific message header value and have a Converter applied to it to convert the value to the declared target type.
• @Headers method argument that is also assignable to Map for access to all headers.
• MessageHeaders method argument for access to all headers.
• MessageHeaderAccessor method argument for access to all headers. In some processing scenarios, like STOMP over WebSocket, this may also be a specialization such as SimpMessageHeaderAccessor.
• Message<T> for access to body and headers with the body de-serialized if necessary to match the declared type.
• Principal method arguments are supported in some processing scenarios such as STOMP over WebSocket. It reflects the authenticated user.

Return value handling depends on the processing scenario:

• STOMP over WebSocket -- the value is turned into a message and sent to a default response destination or to a custom destination specified with an @SendTo or @SendToUser annotation.
• RSocket -- the response is used to reply to the stream request.

Specializations of this annotation include @SubscribeMapping (e.g. STOMP subscriptions) and @ConnectMapping (e.g. RSocket connections). Both narrow the primary mapping further and also match against the message type. Both can be combined with a type-level @MessageMapping that declares a common pattern prefix (or prefixes).

For further details on the use of this annotation in different contexts, see the following sections of the Spring Framework reference:

• STOMP over WebSocket "Annotated Controllers".
• RSocket "Annotated Responders".

NOTE: When using controller interfaces (e.g. for AOP proxying), make sure to consistently put all your mapping annotations - such as @MessageMapping and @SubscribeMapping - on the controller interface rather than on the implementation class.