Dropwizard资源错误响应

Question

In my dropwizard resource, I'm using the built in Jackson JSON object mapping to bind my data.

public class WidgetServiceResource {

    @POST
    @Path("/widget")
    @Produces(MediaType.APPLICATION_JSON)
    public Response foo(ModelParameters c) {
        return Response.ok(c.value).build();
    }

What I noticed however, is when I POST a bad body, the JSON doesn't parse, and I'm served with a response that doesn't meet my company's communication standards. How can I customize the response?

Answer 1

You need to deregister all default exception mappers and then register your own to handle the exception you want:

For example, in your yaml, you need:

server:
  registerDefaultExceptionMappers: false
  rootPath: /api/*
  requestLog:
    appenders: []
  applicationConnectors:
  - type: http
    port: 9085
logging:
  level: INFO

Note: registerDefaultExceptionMappers: false will tell DW to not register any ExceptionMappers.

Then, you can implement them yourself. In my case, I will just do a catch-all handler:

public class MyExceptionMapper  implements ExceptionMapper<Exception>  {
    @Override
    public Response toResponse(Exception exception) {
        return Response.status(400).entity("This makes no sense").build();
    }

}

This reacts to any exception and responds with a 400 and a String.

Finally, registering in the main class:

environment.jersey().register(MyExceptionMapper.class);

And a test for proof:

artur@pandaadb:~/dev/eclipse/eclipse_jee$ curl -v "http://localhost:9085/api/viewTest"
*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 9085 (#0)
> GET /api/viewTest HTTP/1.1
> Host: localhost:9085
> User-Agent: curl/7.47.0
> Accept: */*
> 
< HTTP/1.1 400 Bad Request
< Date: Wed, 12 Oct 2016 10:16:44 GMT
< Content-Type: text/html
< Content-Length: 19
< 
* Connection #0 to host localhost left intact
This makes no sense

Hope that helps,

-- Artur