OpenFeignDemo

OpenFeign demo 服务间调用feign,在进行文件的传递会出现的情况 所使用的是spring boot 2.0 jdk是1.8 要进行pom文件的添加 spring boot 2.0 的feign依赖<br> <dependency><br>    <groupId>org.springframework.cloud</groupId>    <artifactId>spring-cloud-starter-openfeign</artifactId>    <version>2.0.0.RELEASE</version><br> <dependency>

如果要进行服务间调用以formData传递文件的接口,需要引入openfeign文件，如下
<dependency>
      <groupId>io.github.openfeign.form</groupId>
      <artifactId>feign-form</artifactId>
      <version>3.3.0</version>
</dependency>
<dependency>
      <groupId>io.github.openfeign.form</groupId>
      <artifactId>feign-form-spring</artifactId>
      <version>3.3.0</version>
</dependency>

feign接口里面写的接收参数要写@RequestPart如果按照正常写url用@RequestParam的话会报 the request was rejected because no multipart boundary was

同事要在feign里面定义一个配置configuration

  @FeignClient(name = "${service.feign.name}", url = "${service.feign.url:}",
          fallback = TestOpenFeignClient.HystrixClientFallback.class,
          configuration = TestOpenFeignClient.MyConfig.class)
  public interface TestOpenFeignClient extends TestOpenFeignAPI {
  
  
      @Slf4j
      @Component
      class HystrixClientFallback implements TestOpenFeignClient {
          @Override
          public MyResponse testController1() {
              return null;
          }
  
          @Override
          public String testController2() {
              return null;
          }
  
          @Override
          public String test3(MultipartFile multipartFile) {
              return null;
          }
      }
  
      @Configuration
      class MyConfig {
          @Autowired
          private ObjectFactory<HttpMessageConverters> messageConverters;
  
          /**
           * 定义一个解析器,用来解析feign返回的response
           */
          class MyDecoder implements Decoder {
              @Autowired
              private ObjectFactory<HttpMessageConverters> messageConverters;
  
              @Override
              @SuppressWarnings("unchecked")
              public Object decode(Response response, Type type) throws IOException {             
                  if (((Class) type).isAssignableFrom(MyResponse.class)) {
                      MyResponse myResponse = new MyResponse();
                      myResponse.setHeader(response.headers().get("test1").toString());
                      myResponse.setFile(read(response.body().asInputStream()));
                      return myResponse;
                  }                                         
                  return new SpringDecoder(messageConverters).decode(response, type);
              }
  
              private byte[] read(InputStream inStream) throws IOException {
                  ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
                  byte[] buffer = new byte[1024];
                  int len = 0;
                  while ((len = inStream.read(buffer)) != -1) {
                      outputStream.write(buffer, 0, len);
                  }
                  inStream.close();
                  return outputStream.toByteArray();
              }
          }
  
          @Bean
          public Decoder feignDecoder() {
              return new MyDecoder();
          }
  
          @Bean
          public Encoder feignFormEncoder() {
              return new SpringFormEncoder(new SpringEncoder(messageConverters));
          }
      }
  }

配置一个Decoder是为了如果feign调用的接口传回来的是空,文件放到response的流里面等等, 如果不用自己定义的decoder,会什么也收不到,所以需要定义一个Decoder来解析feign传回来的response, 我们可以在feign的response里面获取到我们想要的,也可以不用自己定义Decoder,但是Encoder必须要有, 否则文件无法传送.