骆驼死信频道

Question

I have a route:

from("restlet://RestletBean/{id}?restletMethod=GET")
   .setHeader(Exchange.HTTP_METHOD, constant("GET"))
   .setHeader(Exchange.HTTP_URI, simple("http://x.y.z.com?id={header.id}"))
   .to("http://dummyHost")

When I don't give an appropriate input ( id in this case, which is being used as URI parameter in the to route). The to route will respond me with an error page. Which is not happening. Instead there is a blank white page even after handling using dead letter channel error handler:

from("restlet://RestletBean/{id}?restletMethod=GET").
    .setHeader(Exchange.HTTP_METHOD, constant("GET"))
    .setHeader(Exchange.HTTP_URI, simple("http://x.y.z.com?id={header.id}"))
    .to("http://dummyHost")
    .errorHandler("http://x.y.z.com?id={header.id}");

Answer 1

The dead letter channel does not influence the response. From the Camel doc :

The Dead Letter Channel will redeliver at most 6 times using 1 second delay, and if the exchange failed it will be logged at ERROR level.

By the way, you didn't properly define a dead letter channel in the error handler. It should be:

errorHandler(deadLetterChannel("..."))

Did you try to set throwExceptionOnFailure parameter to true ? From the Camel doc :

Option to disable throwing the HttpOperationFailedException in case of failed responses from the remote server. This allows you to get all responses regardless of the HTTP status code.