Feign中怎么利用httpclient实现文件上传

本篇文章为大家展示了Feign中怎么利用httpclient实现文件上传，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。

Requirements

The feign-form extension depend on OpenFeign and its concrete versions:

• all feign-form releases before 3.5.0 works with OpenFeign 9.* versions;

• starting from feign-form's version 3.5.0, the module works with OpenFeign 10.1.0 versions and greater.

IMPORTANT: there is no backward compatibility and no any gurantee that the feign-form's versions after 3.5.0work with OpenFeign before 10.*. OpenFeign was refactored in 10th release, so the best approach - use the freshest OpenFeign and feign-form versions.

Notes:

• spring-cloud-openfeign uses OpenFeign 9.* till v2.0.3.RELEASE and uses 10.* after. Anyway, the dependency already has suitable feign-form version, see dependency pom, so you don't need to specify it separately;

• spring-cloud-starter-feign is a deprecated dependency and it always uses the OpenFeign's 9.* versions.

使用了如下版本pom，接口httpclient下文件上传内容被篡改问题

feign-version = 9.6.0
<dependency>
    <groupId>io.github.openfeign.form</groupId>
    <artifactId>feign-form</artifactId>
    <version>3.4.1</version>
</dependency>
<dependency>
    <groupId>io.github.openfeign.form</groupId>
    <artifactId>feign-form-spring</artifactId>
    <version>3.4.1</version>
</dependency>
<dependency>
			<groupId>io.github.openfeign</groupId>
			<artifactId>feign-httpclient</artifactId>
			<version>${feign.version}</version>
		</dependency>
		<dependency>
			<groupId>io.github.openfeign</groupId>
			<artifactId>feign-core</artifactId>
			<version>${feign.version}</version>
		</dependency>
		<dependency>
			<groupId>io.github.openfeign</groupId>
			<artifactId>feign-hystrix</artifactId>
			<version>${feign.version}</version>
		</dependency>
		<dependency>
			<groupId>io.github.openfeign</groupId>
			<artifactId>feign-slf4j</artifactId>
			<version>${feign.version}</version>
		</dependency>

多附件文件上传问题

默认SpringFormEncoder只处理单文件，一个强转就完事了

@Override
public void encode (Object object, Type bodyType, RequestTemplate template) throws EncodeException {
  if (!bodyType.equals(MultipartFile.class)) {
    super.encode(object, bodyType, template);
    return;
  }

  val file = (MultipartFile) object;
  val data = singletonMap(file.getName(), object);
  super.encode(data, MAP_STRING_WILDCARD, template);
}

我们系统文件上传支持多附件，这个需要重写下

/**
 * @author yugj
 * @date 2019/8/28 下午4:27.
 */
public class FeignSpringFormEncoder extends FormEncoder {


    /**
     * Constructor with the default Feign's encoder as a delegate.
     */
    public FeignSpringFormEncoder() {
        this(new Default());
    }


    /**
     * Constructor with specified delegate encoder.
     *
     * @param delegate delegate encoder, if this encoder couldn't encode object.
     */
    public FeignSpringFormEncoder(Encoder delegate) {
        super(delegate);

        MultipartFormContentProcessor processor = (MultipartFormContentProcessor) getContentProcessor(ContentType.MULTIPART);
        processor.addWriter(new SpringSingleMultipartFileWriter());
        processor.addWriter(new SpringManyMultipartFilesWriter());
    }


    @Override
    public void encode(Object object, Type bodyType, RequestTemplate template) throws EncodeException {
        if (bodyType.equals(MultipartFile.class)) {
            MultipartFile file = (MultipartFile) object;
            Map data = Collections.singletonMap(file.getName(), object);
            super.encode(data, MAP_STRING_WILDCARD, template);
            return;
        } else if (bodyType.equals(MultipartFile[].class)) {
            MultipartFile[] file = (MultipartFile[]) object;
            if(file != null) {
                Map data = Collections.singletonMap(file.length == 0 ? "" : "file", object);
                super.encode(data, MAP_STRING_WILDCARD, template);
                return;
            }
        }
        super.encode(object, bodyType, template);
    }
}

对应feignclient使用这个配置即可

@Service
@FeignClient(name = "xx-file-sv",
        fallbackFactory = FileGeneralHystrixFallbackAdapter.class,
        configuration = FeignSpringFormEncoder.class)
public interface IFileClient extends IFile {

}

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