HttpMediaTypeNotAcceptableException:在异常处理程序中找不到可接受的表示形式
问题内容:
我的控制器(spring4.1)中有以下图像下载方法:
@RequestMapping(value = "/get/image/{id}/{fileName}", method=RequestMethod.GET)
public @ResponseBody byte[] showImageOnId(@PathVariable("id") String id, @PathVariable("fileName") String fileName) {
setContentType(fileName); //sets contenttype based on extention of file
return getImage(id, fileName);
}
以下ControllerAdvice
方法应处理不存在的文件并返回json错误响应:
@ExceptionHandler(ResourceNotFoundException.class)
@ResponseStatus(HttpStatus.NOT_FOUND)
public @ResponseBody Map<String, String> handleResourceNotFoundException(ResourceNotFoundException e) {
Map<String, String> errorMap = new HashMap<String, String>();
errorMap.put("error", e.getMessage());
return errorMap;
}
我的JUnit测试正常运行
( 编辑 这是由于扩展名.bla:这也适用于appserver):
@Test
public void testResourceNotFound() throws Exception {
String fileName = "bla.bla";
mvc.perform(MockMvcRequestBuilders.get("/get/image/bla/" + fileName)
.with(httpBasic("test", "test")))
.andDo(print())
.andExpect(jsonPath("$error").value(Matchers.startsWith("Resource not found")))
.andExpect(status().is(404));
}
并给出以下输出:
MockHttpServletResponse:
Status = 404
Error message = null
Headers = {X-Content-Type-Options=[nosniff], X-XSS-Protection=[1; mode=block], Cache-Control=[no-cache, no-store, max-age=0, must-revalidate], Pragma=[no-cache], Expires=[0], X-Frame-Options=[DENY], Content-Type=[application/json]}
Content type = application/json
Body = {"error":"Resource not found: bla/bla.bla"}
Forwarded URL = null
Redirected URL = null
Cookies = []
但是在我的应用服务器上,尝试卸载不存在的图像时出现以下错误消息:
( 编辑 这是由于扩展.jpg造成的:这在使用.jpg扩展的JUnit测试中也失败):
ERROR org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver - Failed to invoke @ExceptionHandler method: public java.util.Map<java.lang.String, java.lang.String> nl.krocket.ocr.web.controller.ExceptionController.handleResourceNotFoundException(nl.krocket.ocr.web.backing.ResourceNotFoundException) org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
我已经在我的mvc配置中配置了messageconverters,如下所示:
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
converters.add(mappingJackson2HttpMessageConverter());
converters.add(byteArrayHttpMessageConverter());
}
@Bean
public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter() {
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
//objectMapper.registerModule(new JSR310Module());
MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
converter.setObjectMapper(objectMapper);
converter.setSupportedMediaTypes(getJsonMediaTypes());
return converter;
}
@Bean
public ByteArrayHttpMessageConverter byteArrayHttpMessageConverter() {
ByteArrayHttpMessageConverter arrayHttpMessageConverter = new ByteArrayHttpMessageConverter();
arrayHttpMessageConverter.setSupportedMediaTypes(getImageMediaTypes());
return arrayHttpMessageConverter;
}
我想念什么?为什么JUnit测试有效?
问题答案:
您需要确定Spring应该如何确定响应的媒体类型。这可以通过几种方式完成:
- 路径扩展(例如/image.jpg)
- URL参数(例如?format = jpg)
- HTTP接受标头(例如,接受:图片/ jpg)
默认情况下,Spring会查看 扩展名
而不是Accept
标题。如果您实现@Configuration
扩展的类,则可以更改此行为WebMvcConfigurerAdapter
(或者由于Spring
5.0只是实现WebMvcConfigurer
。您可以在此处覆盖configureContentNegotiation(ContentNegotiationConfigurer configurer)
和配置ContentNegotiationConfigurer
您的需求,例如,通过调用
ContentNegotiationConfigurer#favorParameter
ContentNegotiationConfigurer#favorPathExtension
如果将两者都设置为false
,则Spring将查看Accept
标题。由于您的客户可以说Accept: image/*,application/json
并处理这两种情况,因此Spring应该能够返回图像或错误JSON。