Reading HTTP headers in a Spring REST controller

Question

I am trying to read HTTP headers in Spring based REST API. I followed this. But I am getting this error:

No message body reader has been found for class java.lang.String,
ContentType: application/octet-stream

I am new to Java and Spring so can't figure this out.

This is how my call looks like:

@WebService(serviceName = "common")
@Consumes({ MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON })
@Produces({ MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON })
public interface CommonApiService {

    @GET
    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    @Produces(MediaType.APPLICATION_JSON)
    @Path("/data")
    public ResponseEntity<Data> getData(@RequestHeader(value="User-Agent") String userAgent, @DefaultValue ("") @QueryParam("ID") String id);
}

I have tried @Context: HTTPHeader is null in this case.

How to get values from HTTP headers?

Answer 1

The error that you get does not seem to be related to the RequestHeader.

And you seem to be confusing Spring REST services with JAX-RS, your method signature should be something like:

@RequestMapping(produces = "application/json", method = RequestMethod.GET, value = "data")
@ResponseBody
public ResponseEntity<Data> getData(@RequestHeader(value="User-Agent") String userAgent, @RequestParam(value = "ID", defaultValue = "") String id) {
    // your code goes here
}

And your REST class should have annotations like:

@Controller
@RequestMapping("/rest/")

Regarding the actual question, another way to get HTTP headers is to insert the HttpServletRequest into your method and then get the desired header from there.

Example:

@RequestMapping(produces = "application/json", method = RequestMethod.GET, value = "data")
@ResponseBody
public ResponseEntity<Data> getData(HttpServletRequest request, @RequestParam(value = "ID", defaultValue = "") String id) {
    String userAgent = request.getHeader("user-agent");
}

Don't worry about the injection of the HttpServletRequest because Spring does that magic for you ;)