文件上传Spring Cloud Feign客户端

debugcn 发表于 Dev

ZiOS

当使用spring cloud netflix的伪客户端从一个微服务向另一个微服务发出发布请求时，Postman中出现以下错误：

{
"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：未找到类java.io.FileDescriptor的序列化程序，也未找到创建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”]），位于com.fasterxml.jackson.databind.JsonMappingException.from（JsonMappingException.java:284）〜[jackson-databind-2.8。 com.fasterxml.jackson.databind.SerializerProvider.mappingException（SerializerProvider.java:1110）的[jar.2.8.9]〜com.fasterxml.jackson的[jackson-databind-2.8.9.jar：2.8.9]。 databind.SerializerProvider.reportMappingProblem（SerializerProvider.java:1135）〜[jackson-databind-2.8.9.jar：2.8.9]位于com.fasterxml.jackson。databind.ser.impl.UnknownSerializer.failForEmpty（UnknownSerializer.java:69）〜[jackson-databind-2.8.9.jar：2.8.9] at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.serialize（UnknownSerializer .java：32）〜[jackson-databind-2.8.9.jar：2.8.9]，位于com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField（BeanPropertyWriter.java:704）〜[jackson-databind-2.8。 com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields（BeanSerializerBase.java:689）的9.jar：2.8.9]〜com的[jackson-databind-2.8.9.jar：2.8.9]。 fastxml.jackson.databind.ser.BeanSerializer.serialize（BeanSerializer.java:155）〜[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]，位于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.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]位于com.fasterxml.jackson.databind.ObjectWriter.writeValue（ObjectWriter。 java：951）〜[jackson-databind-2.8.9.jar：2.8.9]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]，位于com.fasterxml.jackson.databind.ObjectWriter.writeValue（ObjectWriter.java:951）〜[jackson-databind-2.8.9.jar：2.8.9]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]，位于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);
}

}

我肯定在这里缺少某种串行器。
任何建议将不胜感激！
谢谢

马丁·乔林

经过几天的寻找解决方案，我发现了这一点。您应该开始为spring依赖添加伪装形式：

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

然后您的假客户需要这个spring表格编码器：

@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();
    }
  }
}

希望对您有所帮助。

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