java - 文件上传spring cloud feign客户端

Question

当使用 spring cloud netflix 的 feign 客户端从一个微服务向另一个微服务发出 post 请求时，我在 Postman 中收到以下错误：

{
"timestamp": 1506933777413,
"status": 500,
"error": "Internal Server Error",
"exception": "feign.codec.EncodeException",
"message": "Could not write JSON: No serializer found for class java.io.FileDescriptor and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS); nested exception is com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class java.io.FileDescriptor and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile[\"inputStream\"]->java.io.FileInputStream[\"fd\"])",
"path": "/attachments"
}

我的 Eclipse 控制台显示以下异常：

com.fasterxml.jackson.databind.JsonMappingException：没有为类 java.io.FileDescriptor 找到序列化程序，也没有发现用于创建 BeanSerializer 的属性（为避免异常，请禁用 SerializationFeature.FAIL_ON_EMPTY_BEANS）（通过参考链：org.springframework.web.multipart。 support.StandardMultipartHttpServletRequest$StandardMultipartFile["inputStream"]->java.io.FileInputStream["fd"]) at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:284) ~[jackson-databind-2.8. 9.jar:2.8.9] 在 com.fasterxml.jackson.databind.SerializerProvider.mappingException(SerializerProvider.java:1110) ~[jackson-databind-2.8.9.jar:2.8.9] 在 com.fasterxml.jackson。 databind.SerializerProvider.reportMappingProblem(SerializerProvider.java:1135) ~[jackson-databind-2.8.9.jar:2.8.9] 在 com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.failForEmpty(UnknownSerializer.java:69) ~[jackson-databind-2.8.9.jar:2.8.9] 在 com.fasterxml.jackson.databind。 ser.impl.UnknownSerializer.serialize(UnknownSerializer.java:32) ~[jackson-databind-2.8.9.jar:2.8.9] at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:704 ) ~[jackson-databind-2.8.9.jar:2.8.9] at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:689) ~[jackson-databind-2.8.9. jar:2.8.9] 在 com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.8.9.jar:2.8.9] 在 com.fasterxml.jackson。 databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:704) ~[jackson-databind-2.8.9.jar:2.8.9] 在 com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:689) ~[jackson-databind-2.8.9.jar:2.8.9] 在 com.fasterxml.jackson.databind。 ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.8.9.jar:2.8.9] at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:292) ~ [jackson-databind-2.8.9.jar:2.8.9] 在 com.fasterxml.jackson.databind.ObjectWriter$Prefetch.serialize(ObjectWriter.java:1429) ~[jackson-databind-2.8.9.jar:2.8。 9] 在 com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:951) ~[jackson-databind-2.8.9.jar:2.8.9]jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.8.9.jar:2.8.9] at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java :292) ~[jackson-databind-2.8.9.jar:2.8.9] at com.fasterxml.jackson.databind.ObjectWriter$Prefetch.serialize(ObjectWriter.java:1429) ~[jackson-databind-2.8.9。 jar:2.8.9] 在 com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:951) ~[jackson-databind-2.8.9.jar:2.8.9]jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.8.9.jar:2.8.9] at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java :292) ~[jackson-databind-2.8.9.jar:2.8.9] at com.fasterxml.jackson.databind.ObjectWriter$Prefetch.serialize(ObjectWriter.java:1429) ~[jackson-databind-2.8.9。 jar:2.8.9] 在 com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:951) ~[jackson-databind-2.8.9.jar:2.8.9]序列化（ObjectWriter.java:1429）~[jackson-databind-2.8.9.jar:2.8.9] at com.fasterxml.jackson.databind.ObjectWriter.writeValue（ObjectWriter.java:951）~[jackson-databind-2.8 .9.jar:2.8.9]序列化（ObjectWriter.java:1429）~[jackson-databind-2.8.9.jar:2.8.9] at com.fasterxml.jackson.databind.ObjectWriter.writeValue（ObjectWriter.java:951）~[jackson-databind-2.8 .9.jar:2.8.9]

更新 1

这是我的假装界面：

@FeignClient(name="attachment-service", fallback=AttachmentHystrixFallback.class)
public interface AttachmentFeignClient {

@RequestMapping("upload")
void upload(@RequestPart(name="file") MultipartFile file, @RequestParam(name="attachableId") Long attachableId, 
        @RequestParam(name="className") String className, @RequestParam(name="appName") String appName);

这是主要的微服务控制器：

@RestController
public class AttachmentController implements Serializable {

/**
 * 
 */
private static final long serialVersionUID = -4431842080646836475L;

@Autowired
AttachmentService attachmentService;

@RequestMapping(value = "attachments", method = RequestMethod.POST, consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
public void upload(@RequestPart MultipartFile file, @RequestParam Long attachableId, @RequestParam String className, @RequestParam String appName) throws Exception {
    attachmentService.uploadFile(file, attachableId, className, appName);
}

}

我当然在这里缺少某种序列化程序
任何建议将不胜感激！
谢谢

score 15 · Accepted Answer

经过几天搜索解决方案后，我发现了这一点。您应该开始为 spring 依赖添加 feign 形式：

<dependency>
   <groupId>io.github.openfeign.form</groupId>
   <artifactId>feign-form-spring</artifactId>
   <version>3.3.0</version>
</dependency

然后你的假装客户需要这个弹簧形式的编码器：

@FeignClient(
    name="attachment-service",  
    configuration = {AttachmentFeignClient.MultipartSupportConfig.class}
    fallback=AttachmentHystrixFallback.class)
public interface AttachmentFeignClient {

@RequestMapping(value= {"upload"}, consumes = {"multipart/form-data"})
void upload(
    @RequestPart(name="file") MultipartFile file, 
    @RequestParam(name="attachableId") Long attachableId, 
    @RequestParam(name="className") String className,
    @RequestParam(name="appName") String appName);

 public class MultipartSupportConfig {
    @Bean
    @Primary
    @Scope("prototype")
    public Encoder feignFormEncoder() {
        return new SpringFormEncoder();
    }
  }
}

我希望它会帮助某人。

score 8 · Accepted Answer

更新 13/01/2020
配置 FeignClient 以使用 @RequestPart 处理 MultiPartFile
请注意，仅当您有一个代表整个主体的 RequestPart 时，此方法才适用。拥有多个 RequestPart 是 FeignClient 的另一个问题。

feignclient 的配置类似于@marting-choraine 所做的，但在 FeignConfigurationClass 中添加了额外的 Encoder Configuration。

因此，对于我在下面提供的相同示例，您需要执行类似这样的操作，而不是实现自定义映射器

@Configuration
@EnableFeignClients(basePackages = "YourPackage")
public class FeignConfiguration {

  @Bean
  public Encoder feignFormEncoder(ObjectFactory<HttpMessageConverters> messageConverters) {
      return new SpringFormEncoder(new SpringEncoder(messageConverters));
  }
}

TL;DR
将您的 MultiPartFile 转换为 MultiValueMap。请参阅下面的示例

@martin-choraine提到的答案是拥有 FeignClient 方法签名的正确和最佳答案，与您尝试调用的实际端点签名相同。但是，有一种方法不需要您定义 FormEncoder 或添加任何额外的依赖项，因为在某些应用程序中您不允许这样做（企业狗屎）；您所需要的只是将您的 MultipartFile 转换为 MultiValueMap ，它将完美地工作，因为标准编码器将能够对其进行序列化。

要调用的实际端点

@PostMapping(path = "/add", consumes = MULTIPART_FORM_DATA_VALUE, produces = APPLICATION_JSON_VALUE)
 public MyResponseObject add(@RequestParam(name = "username") String username,
                             @RequestPart(name = "filetoupload") MultipartFile file) {
              Do something
}

FeignClient 中的 POST 方法应如下所示

@PostMapping(path = "/myApi/add", consumes = MULTIPART_FORM_DATA_VALUE, 
              produces = APPLICATION_JSON_VALUE)
 public MyResponseObject addFile(@RequestParam(name = "username") String username,
                           @RequestPart(name = "filetoupload") MultiValueMap<String, Object> file);

然后，当您调用 addFile 时，您应该像这样提供 MultiValueMap

public MyResponseObject addFileInAnotherEndPoint(String username, MultipartFile file) throws IOException {

    MultiValueMap<String, Object> multiValueMap = new LinkedMultiValueMap<>();
    ByteArrayResource contentsAsResource = new ByteArrayResource(file.getBytes()) {
        @Override
        public String getFilename() {
            return file.getOriginalFilename();
        }
    };
    multiValueMap.add("filetoupload", contentsAsResource);
    multiValueMap.add("fileType", file.getContentType());
    return this.myFeignClient.addFile(username, multiValueMap);
}

score 1 · Accepted Answer

我在帖子中添加了 consumes = MediaType.MULTIPART_FORM_DATA_VALUE，它对我有用。这是我的假客户端方法，在前面我使用了formdata

@PostMapping(path=Urls.UPLOAD_FILE_IN_LIBELLE, consumes = MediaType.MULTIPART_FORM_DATA_VALUE )
    public void uploadFileInLibelle(
            @RequestParam String processus,
            @RequestParam String level0Name,
            @RequestParam String nomFichier,
            @RequestParam String nomLibelle,
            @RequestParam String anneeFolderName,
            @RequestParam String semaineFolderName,
            @RequestPart   MultipartFile fichier);

这是我的角前端

public uploadFiles(
        nomFichier: string,
        nomLibelle: string,
        processus: string,
        level0Name: string,
        semaineFolderName: string,
        anneeFolderName: string,
        byte: File
    ): Observable<any> {
        const formData = new FormData();
        formData.set('processus', processus);
        formData.set('level0Name', level0Name);
        formData.set('nomLibelle', nomLibelle);
        formData.set('anneeFolderName', anneeFolderName);
        formData.set('semaineFolderName', semaineFolderName);
        formData.set('nomFichier', nomFichier);
        formData.set('fichier', byte);

        return this.httpClient.post(this.urlUploadFile, formData);
    }

java - 文件上传spring cloud feign客户端

3 回答 3

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