@GetMapping is called even when Accept is defined how null

问题

I am working with Spring Framework 4.3.13.RELEASE

About Rest, for POST, I have the following:

@Controller
@RequestMapping(path="/personas")
public class PersonaRestController {

    @PostMapping(consumes={MediaType.APPLICATION_XML_VALUE, MediaType.APPLICATION_JSON_UTF8_VALUE})
    public ResponseEntity<Void> saveOne(
            @Validated @RequestBody Persona persona, ...

About Testing working with JUnit and with ResultActions I can get the java.lang.AssertionError: No handler error message and confirm the following:

MockHttpServletRequest:
      HTTP Method = POST
      Request URI = /personas
       Parameters = {}
          Headers = {}

Handler:
             Type = null

Async:
    Async started = false
     Async result = null

Resolved Exception:
             Type = org.springframework.web.HttpMediaTypeNotSupportedException

ModelAndView:
        View name = null
             View = null
            Model = null

FlashMap:
       Attributes = null

MockHttpServletResponse:
           Status = 415
    Error message = null
          Headers = {Accept=[application/xml, application/json;charset=UTF-8]}
     Content type = null
             Body = 
    Forwarded URL = null
   Redirected URL = null
          Cookies = []

Has sense this behaviour because the saveOne method expects the content data be either XML or JSON and for this test scenario the Content-Type was not sent.

Therefore is expected that Spring arises a HttpMediaTypeNotSupportedException instance. Then the @Test method fails and the java.lang.AssertionError: No handler error message appears because there is no a handler to handle the user request.

Until here all OK.

Again, about Rest, for GET, I have the following:

@GetMapping(path="/{id}",
            produces={MediaType.APPLICATION_XML_VALUE, MediaType.APPLICATION_JSON_UTF8_VALUE})
public @ResponseBody Persona findOneById(@PathVariable String id){
    return personaService.findOneById(id);
}

For other Testing scenario with the following:

MockHttpServletRequest:
      HTTP Method = GET
      Request URI = /personas/100
       Parameters = {}
          Headers = {}

Handler:
             Type = com.manuel.jordan.rest.persona.PersonaRestController
           Method = public com.manuel.jordan.domain.Persona com.manuel.jordan.rest.persona.PersonaRestController.findOneById(java.lang.String)

My interceptor shows the following data

HttpHeaderControlInterceptor - preHandle 
   HttpServletRequest > 
    URL: http://localhost/personas/100 
    URI: /personas/100 
       HttpMethod: GET 
          Accept: null 
          Accept-Language: null 
          Content-Type: null

I am confused why the findOneById method was called how a handler even when Accept was null. I had expected something similar than the java.lang.AssertionError: No handler error message and the HttpMediaTypeNotAcceptableException class instead, it because the findOneById method can return the data in either XML or JSON

What is missing?

回答1:

I am not fully sure but guess that its caused by HTTP 1.1 ,

See Section - 10.4.7 406 Not Acceptable here

Note: HTTP/1.1 servers are allowed to return responses which are not acceptable according to the accept headers sent in the request. In some cases, this may even be preferable to sending a 406 response. User agents are encouraged to inspect the headers of an incoming response to determine if it is acceptable.

I think, treatment of consumes vs produces is different and that is why you see the difference.

Refer to this SO question here

I had posted an answer before that I have deleted. Basically, I had misunderstood your question.

来源：https://stackoverflow.com/questions/48054312/getmapping-is-called-even-when-accept-is-defined-how-null

标签

Spring

spring-mvc

spring-rest