java - 为什么我的 Controller 发送内容类型 "application/octet-stream"？

Question

我有一个 REST Controller :

@RequestMapping(value = "greeting", method = RequestMethod.GET, produces = "application/json; charset=utf-8")
@Transactional(readOnly = true)
@ResponseBody
public HttpEntity<GreetingResource> greetingResource(@RequestParam(value = "message", required = false, defaultValue = "World") String message) {
    GreetingResource greetingResource = new GreetingResource(String.format(TEMPLATE, message));
    greetingResource.add(linkTo(methodOn(AdminController.class).greetingResource(message)).withSelfRel());
    HttpHeaders responseHeaders = new HttpHeaders();
    responseHeaders.add("Content-Type", "application/json; charset=utf-8");
    return new ResponseEntity<GreetingResource>(greetingResource, responseHeaders, HttpStatus.OK);
}

如您所见，我正在努力指定 Controller 返回的内容类型。

它是通过 REST 客户端访问的:

public String getGreetingMessage() {
    String message;
    try {
        HttpHeaders httpHeaders = Common.createAuthenticationHeaders("stephane" + ":" + "mypassword");
        ResponseEntity<GreetingResource> responseEntity = restTemplate.getForEntity("/admin/greeting", GreetingResource.class, httpHeaders);
        GreetingResource greetingResource = responseEntity.getBody();
        message = greetingResource.getMessage();
    } catch (HttpMessageNotReadableException e) {
        message = "The GET request FAILED with the message being not readable: " + e.getMessage();
    } catch (HttpStatusCodeException e) {
        message = "The GET request FAILED with the HttpStatusCode: " + e.getStatusCode() + "|" + e.getStatusText();
    } catch (RuntimeException e) {
        message = "The GET request FAILED " + ExceptionUtils.getFullStackTrace(e);
    }
    return message;
}

http header 由实用程序创建:

static public HttpHeaders createAuthenticationHeaders(String usernamePassword) {
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.APPLICATION_JSON);
    headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
    byte[] encodedAuthorisation = Base64.encode(usernamePassword.getBytes());
    headers.add("Authorization", "Basic " + new String(encodedAuthorisation));
    return headers;
}

网络安全配置和代码运行良好。我使用基于 mockMvc 的集成测试来确保这一点成功。

唯一失败的测试是基于 REST 模板的测试:

@Test
public void testGreeting() throws Exception {
    mockServer.expect(requestTo("/admin/greeting")).andExpect(method(HttpMethod.GET)).andRespond(withStatus(HttpStatus.OK));
    String message = adminRestClient.getGreetingMessage();
    mockServer.verify();
    assertThat(message, allOf(containsString("Hello"), containsString("World")));
}

Maven 构建控制台输出中给出的异常是:

java.lang.AssertionError: 
Expected: (a string containing "Hello" and a string containing "World")
got: "The GET request FAILED org.springframework.web.client.RestClientException : Could not extract response: no suitable HttpMessageConverter found for response type [class com.thalasoft.learnintouch.rest.resource.GreetingR esource] and content type [application/octet-stream]\n\tat org.springframework.web.client.HttpMessageConverte rExtractor.extractData(HttpMessageConverterExtract or.java:107)

我在 Java 1.6 版本上使用 Spring Framework 3.2.2.RELEASE 版本和 Spring Security 3.1.4.RELEASE 版本。

首先，我有一个简单的 REST 模板:

@Bean
public RestTemplate restTemplate() {
    RestTemplate restTemplate = new RestTemplate();
    return restTemplate;
}

我现在添加了它，希望它会有所帮助:

private static final Charset UTF8 = Charset.forName("UTF-8");

@Bean
public RestTemplate restTemplate() {
    List<HttpMessageConverter<?>> messageConverters = new ArrayList<HttpMessageConverter<?>>();
    MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter();        
    mappingJackson2HttpMessageConverter.setSupportedMediaTypes(Arrays.asList(new MediaType("application", "json", UTF8)));
    messageConverters.add(mappingJackson2HttpMessageConverter);

    Jaxb2Marshaller jaxb2Marshaller = new Jaxb2Marshaller();
    jaxb2Marshaller.setClassesToBeBound(new Class[] {
        GreetingResource.class
    });
    MarshallingHttpMessageConverter marshallingHttpMessageConverter = new MarshallingHttpMessageConverter(jaxb2Marshaller, jaxb2Marshaller);
    messageConverters.add(marshallingHttpMessageConverter);

    messageConverters.add(new ByteArrayHttpMessageConverter());
    messageConverters.add(new FormHttpMessageConverter());
    StringHttpMessageConverter stringHttpMessageConverter = new StringHttpMessageConverter();
    stringHttpMessageConverter.setSupportedMediaTypes(Arrays.asList(new MediaType("text", "plain", UTF8)));
    messageConverters.add(stringHttpMessageConverter);
    messageConverters.add(new BufferedImageHttpMessageConverter());
    messageConverters.add(new Jaxb2RootElementHttpMessageConverter());
    messageConverters.add(new AllEncompassingFormHttpMessageConverter());
    RestTemplate restTemplate = new RestTemplate();
    restTemplate.setMessageConverters(messageConverters);
    return restTemplate;
}

但它没有改变任何东西，异常保持不变。

我的理解是，它不是 REST 模板需要任何特定的 JSON 配置，而是，由于某种原因，我的 Controller 吐出一些 application/octet-stream 内容类型而不是一些 application/json 内容类型。

有什么线索吗？

一些附加信息...

Web 测试配置中的管理休息客户端 bean:

@Configuration
public class WebTestConfiguration {

    @Bean
    public AdminRestClient adminRestClient() {
        return new AdminRestClient();
    }

    @Bean
    public RestTemplate restTemplate() {
        List<HttpMessageConverter<?>> messageConverters = new ArrayList<HttpMessageConverter<?>>();
        MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter();        
        mappingJackson2HttpMessageConverter.setSupportedMediaTypes(Arrays.asList(new MediaType("application", "json", UTF8)));
        messageConverters.add(mappingJackson2HttpMessageConverter);

        Jaxb2Marshaller jaxb2Marshaller = new Jaxb2Marshaller();
        jaxb2Marshaller.setClassesToBeBound(new Class[] {
            Greeting.class
        });
        MarshallingHttpMessageConverter marshallingHttpMessageConverter = new MarshallingHttpMessageConverter(jaxb2Marshaller, jaxb2Marshaller);
        messageConverters.add(marshallingHttpMessageConverter);

        messageConverters.add(new ByteArrayHttpMessageConverter());
        messageConverters.add(new FormHttpMessageConverter());
        StringHttpMessageConverter stringHttpMessageConverter = new StringHttpMessageConverter();
        stringHttpMessageConverter.setSupportedMediaTypes(Arrays.asList(new MediaType("text", "plain", UTF8)));
        messageConverters.add(stringHttpMessageConverter);
        messageConverters.add(new BufferedImageHttpMessageConverter());
        messageConverters.add(new Jaxb2RootElementHttpMessageConverter());
        messageConverters.add(new AllEncompassingFormHttpMessageConverter());
        RestTemplate restTemplate = new RestTemplate();
        restTemplate.setMessageConverters(messageConverters);
        return restTemplate;
    }

}

基本测试类:

@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration( classes = { ApplicationConfiguration.class, WebSecurityConfig.class, WebConfiguration.class, WebTestConfiguration.class })
@Transactional
public abstract class AbstractControllerTest {

    @Autowired
    private WebApplicationContext webApplicationContext;

    @Autowired
    private FilterChainProxy springSecurityFilterChain;

    @Autowired  
    protected RestTemplate restTemplate;  

    protected MockRestServiceServer mockServer;

    @Before
    public void setup() {
        this.mockServer = MockRestServiceServer.createServer(restTemplate);
    }

}

网络初始化类:

public class WebInit implements WebApplicationInitializer {

    private static Logger logger = LoggerFactory.getLogger(WebInit.class);

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        registerListener(servletContext);

        registerDispatcherServlet(servletContext);

        registerJspServlet(servletContext);

        createSecurityFilter(servletContext);
    }

    private void registerListener(ServletContext servletContext) {
        // Create the root application context
        AnnotationConfigWebApplicationContext appContext = createContext(ApplicationConfiguration.class, WebSecurityConfig.class);

        // Set the application display name
        appContext.setDisplayName("LearnInTouch");

        // Create the Spring Container shared by all servlets and filters
        servletContext.addListener(new ContextLoaderListener(appContext));
    }

    private void registerDispatcherServlet(ServletContext servletContext) {
        AnnotationConfigWebApplicationContext webApplicationContext = createContext(WebConfiguration.class);

        ServletRegistration.Dynamic dispatcher = servletContext.addServlet("dispatcher", new DispatcherServlet(webApplicationContext));
        dispatcher.setLoadOnStartup(1);

        Set<String> mappingConflicts = dispatcher.addMapping("/");

        if (!mappingConflicts.isEmpty()) {
          for (String mappingConflict : mappingConflicts) {
            logger.error("Mapping conflict: " + mappingConflict);
          }
          throw new IllegalStateException(
              "The servlet cannot be mapped to '/'");
        }
    }

    private void registerJspServlet(ServletContext servletContext) {
    }

    private AnnotationConfigWebApplicationContext createContext(final Class... modules) {
        AnnotationConfigWebApplicationContext appContext = new AnnotationConfigWebApplicationContext();
        appContext.register(modules);
        return appContext;
    }

    private void createSecurityFilter(ServletContext servletContext) {
        FilterRegistration.Dynamic springSecurityFilterChain = servletContext.addFilter("springSecurityFilterChain", DelegatingFilterProxy.class);
        springSecurityFilterChain.addMappingForUrlPatterns(null, false, "/*");
    }

}

网络配置:

@Configuration
@EnableWebMvc
@EnableEntityLinks
@ComponentScan(basePackages = "com.thalasoft.learnintouch.rest.controller")
public class WebConfiguration extends WebMvcConfigurerAdapter {

    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
        PageableArgumentResolver resolver = new PageableArgumentResolver();
        resolver.setFallbackPageable(new PageRequest(1, 10));
        resolvers.add(new ServletWebArgumentResolverAdapter(resolver));
        super.addArgumentResolvers(resolvers);
    }

}

应用程序配置目前为空:

@Configuration
@Import({ ApplicationContext.class })
public class ApplicationConfiguration extends WebMvcConfigurerAdapter {

    // Declare "application" scope beans here, that is, beans that are not only used by the web context

}

Answer 1

我之前也有疑问，但现在你已经发布了所有内容，这就是事实。假设您在 getGreetingMessage() 方法中使用的 RestTemplate 对象与 @Bean 方法中声明的对象相同，问题就从这里开始

this.mockServer = MockRestServiceServer.createServer(restTemplate);

此调用会覆盖 RestTemplate 对象在内部通过模拟使用的默认 ClientHttpRequestFactory 对象。在您的 getGreetingMessage() 方法中，此调用

ResponseEntity<GreetingResource> responseEntity = restTemplate.getForEntity("/admin/greeting", GreetingResource.class, httpHeaders);

实际上并不通过网络。 RestTemplate 使用模拟的 ClientHttpRequestFactory 创建一个假的 ClientHttpRequest，它生成一个假的 ClientHttpResponse，它没有Content-Type header 。当 RestTemplate 查看 ClientHttpResponse 以确定其 Content-Type 但没有找到时，它会假定 application/octet-默认情况下流。

因此，您的 Controller 没有设置内容类型，因为您的 Controller 从未被命中。 RestTemplate 正在为您的响应使用默认内容类型，因为它是模拟的并且实际上并不包含该内容类型。

<小时/>

来自您的评论:

I wonder if I understand what the mock server is testing. I understand it is to be used in acceptance testing scenario. Is it supposed to hit the controller at all ?

MockRestServiceServer 的 javadoc状态:

Main entry point for client-side REST testing. Used for tests that involve direct or indirect (through client code) use of the RestTemplate. Provides a way to set up fine-grained expectations on the requests that will be performed through the RestTemplate and a way to define the responses to send back removing the need for an actual running server.

换句话说，就好像您的应用程序服务器不存在一样。因此，您可以抛出您想要的任何期望(和实际返回值)并测试客户端发生的任何情况。因此，您不是在测试服务器，而是在测试客户端。

您确定您不是在寻找 MockMvc ，即

Main entry point for server-side Spring MVC test support.

您可以设置它以在集成环境中实际使用您的@Controller bean。您实际上并未发送 HTTP 请求，但 MockMvc 正在模拟它们的发送方式以及您的服务器将如何响应。