Java &引用；“未设置内容类型”；单元测试Spring RESTful控制器时

我有一个与此类似的Rest控制器：

@RestController
public class UserRestController {

    @Autowired
    private UserService userService;

    @RequestMapping(value = "/user/activate", method = RequestMethod.POST)
    public ResponseEntity<UserDTO> activate(
            @RequestParam(required = true) final String email,
            @RequestParam(required = true) final String key) {

        UserDTO userDTO = userService.activateAccount(email, key);
        return new ResponseEntity<UserDTO>(userDTO, HttpStatus.OK);
    }
}

另一方面，我正在用JUnit和MockMVC Spring实用程序测试这个方法

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = ApplicationConfig.class)
@WebAppConfiguration
public class UserRestControllerTest {

    private static MockMvc mockMvc;

    @Mock
    private UserService userService;

    @InjectMocks
    private UserRestController userRestController;

    @Before
    public void setup() {

        MockitoAnnotations.initMocks(this);
        mockMvc = MockMvcBuilders
                .standaloneSetup(userRestController)
                .setMessageConverters(
                        new MappingJackson2HttpMessageConverter(),
                        new Jaxb2RootElementHttpMessageConverter()).build();

    }

    @Test
    public void testActivateRequiredParams() throws Exception {

        mockMvc.perform(
                MockMvcRequestBuilders.post("/user/activate")
                .contentType(MediaType.APPLICATION_FORM_URLENCODED)
                .accept(MediaType.APPLICATION_JSON))
                .andDo(MockMvcResultHandlers.print())
                .andExpect(MockMvcResultMatchers.status().isBadRequest())
                .andExpect(
                        MockMvcResultMatchers.content().contentType(
                                UtilsUnitTest.APPLICATION_JSON_UTF8))
                .andExpect(
                        jsonPath(
                                "message",
                                is("Required String parameter 'email' is not present")));

     }
}

但是当我执行这个测试时，我注意到响应不是JSON消息。事实上，我有一个例外：

java.lang.AssertionError:未设置内容类型

特别是，完成的结果是

MockHttpServletRequest:
         HTTP Method = POST
         Request URI = /user/activate
          Parameters = {}
             Headers = {Content-Type=[application/x-www-form-urlencoded]}

             Handler:
                Type = com.company.controller.UserRestController
              Method = public org.springframework.http.ResponseEntity<com.company.dto.UserDTO> com.company.controller.UserRestController.activate(java.lang.String,java.lang.String)

               Async:
       Async started = false
        Async result = null

  Resolved Exception:
                Type = org.springframework.web.bind.MissingServletRequestParameterException

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

            FlashMap:

MockHttpServletResponse:
              Status = 400
       Error message = Required String parameter 'email' is not present
             Headers = {}
        Content type = null
                Body = 
       Forwarded URL = null
      Redirected URL = null
             Cookies = []

MockHttpServletRequest:
HTTP方法=POST
请求URI=/user/activate
参数={}
Headers={Content Type=[application/x-www-form-urlencoded]}
处理程序：
Type=com.company.controller.UserRestController
Method=public org.springframework.http.ResponseEntity.com.company.controller.UserRestController.activate（java.lang.String，java.lang.String）
异步：
异步启动=错误
异步结果=空
已解决的异常：
Type=org.springframework.web.bind.MissingServletRequestParameterException
ModelAndView：
视图名称=空
视图=空
模型=空
FlashMap：
MockHttpServletResponse：
状态=400
错误消息=所需字符串参数“email”不存在
标题={}
内容类型=空
正文=
转发的URL=null
重定向的URL=null
Cookies=[]

我推断，当抛出异常时，不会将其转换为JSON格式（当我发送电子邮件和关键参数时，会得到正确的JSON结果）

---

问题很明显：在抛出异常的情况下，我应该在单元测试配置中更改什么以获取JSON错误消息

问题在于，在以下断言失败后，测试停止：

.andExpect(MockMvcResultMatchers.content().contentType(UtilsUnitTest.APPLICATION_JSON_UTF8))

除此之外，

jsonPath（“message”…

不会命中任何内容。要验证返回的错误消息，请使用

MockMvcResultMatchers.status（）.reason（）

以下测试应完成此工作：

@Test
public void testActivateRequiredParams() throws Exception {
    final ResultActions result = mockMvc
            .perform(MockMvcRequestBuilders.post("/user/activate")
                    .contentType(MediaType.APPLICATION_FORM_URLENCODED).accept(MediaType.APPLICATION_JSON))
            .andDo(MockMvcResultHandlers.print());
    result.andExpect(MockMvcResultMatchers.status().isBadRequest());
    result.andExpect(MockMvcResultMatchers.status().reason(is("Required String parameter 'email' is not present")));
}

但是想想看，如果这（测试错误消息）总体上是一个好主意，也许可以看到

@Test
public void testActivateRequiredParams() throws Exception {
    final ResultActions result = mockMvc
            .perform(MockMvcRequestBuilders.post("/user/activate")
                    .contentType(MediaType.APPLICATION_FORM_URLENCODED).accept(MediaType.APPLICATION_JSON))
            .andDo(MockMvcResultHandlers.print());
    result.andExpect(MockMvcResultMatchers.status().isBadRequest());
    result.andExpect(MockMvcResultMatchers.status().reason(is("Required String parameter 'email' is not present")));
}