Springboot+ SpringCloud FeignClient发送MultipartFile

1.服务端

1.1 服务端（文件接收方）接口：

 @ApiOperation(value = \"保存备份文件\", notes = \"保存备份文件\", consumes = MediaType.MULTIPART_FORM_DATA_VALUE, produces = \"application/json\")
    @PostMapping(value = \"/saveBackFile\")
    @ResponseBody
    public Response saveBackFile(
            @ApiParam(value = \"文件附加信息\") @Valid BackupFileAttachInfo fileInfo,
            @ApiParam(value = \"备份文件\") @RequestPart(\"file\") MultipartFile file);

1.2 服务端增加一个对象注入（可通过一个配置类的方法注入），配置文件上传临时目录

 @Bean
    public MultipartConfigElement multipartConfigElement() {
        MultipartConfigFactory factory = new MultipartConfigFactory();
        factory.setLocation(\"d:/\"); //配置文件上传临时目录
        return factory.createMultipartConfig();
    }

2.客户端

2.0 SpringBoot启动类要增加  @EnableFeignClients 注解，否则，FeignClient不会生效！

2.1 首先pom中要增加feign和eureka等的依赖，还要加入下面的依赖：

       <!--添加Springboot对MultipartFile的类库支持，在spring-test包中-->
        <dependency>
            <groupId>org.spring work</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.1.3.RELEASE</version>
            <scope>compile</scope>
        </dependency>
        <!--spring feign form 表单提交相关-->
        <dependency>
            <groupId>io.github.openfeign.form</groupId>
            <artifactId>feign-form-spring</artifactId>
            <version>3.4.1</version>
        </dependency>
        <!--feign form 表单提交相关-->
        <dependency>
            <groupId>io.github.openfeign.form</groupId>
            <artifactId>feign-form</artifactId>
            <version>3.4.1</version>
        </dependency>
        <!--文件上传相关依赖-->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.3</version>
        </dependency>

2.2 FeignClient

@Service
@FeignClient(name = \"MODEL-LIB\",value=\"MODEL-LIB\" , configuration = FeignMultipartSupportConfig.class,url=\"http://127.0.0.1:8080/file\") 
public interface ModellibFeignClient {
    @PostMapping(value = \"/saveBackFile\" ,consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
    @ResponseBody
    public  Responsev1 saveBackFile(
            @ApiParam(value = \"租户id\") @RequestParam(\"tenant\") String tenant,
            @ApiParam(value = \"project\") @RequestParam(\"project\") String project,
            @ApiParam(value = \"namespace\") @RequestParam(\"namespace\") String namespace,
            @ApiParam(value = \"username\") @RequestParam(\"username\") String username,
            @ApiParam(value = \"备份文件\")  @RequestPart(\"file\")  MultipartFile file);
}

2.3 Feign配置类，主要是对MultipartFile上传时的编码相关：FeignMultipartSupportConfig，如果不配置这个类，默认会将文件也编译成json，导致报错：

@Configuration
public class FeignMultipartSupportConfig {
    @Autowired
    private  Factory<HttpMessageConverters> messageConverters;

    @Bean
    @Primary
    @Scope(\"prototype\")
    public Encoder multipartFormEncoder() {
        return new SpringFormEncoder(new SpringEncoder(messageConverters));
    }

    @Bean
    public feign.Logger.Level multipartLoggerLevel() {
        return Logger.Level.FULL;
    }
}

2.4 调用FeignClient

                    File file = new File(\"d://lq.jpg\");

                    MultipartFile multipartFile = null;

                    DiskFileItem fileItem = (DiskFileItem) new DiskFileItemFactory().createItem(\"file\", //这个file对应feignClient中的MultipartFile参数名，写错就会报400 ：\"message\":\"Required request part \'file\' is not present\"这个错误，切记！
                            MediaType.MULTIPART_FORM_DATA_VALUE, true, file.getName());

                    try (InputStream input = new FileInputStream(file); OutputStream os = fileItem.getOutputStream()) {
                        IOUtils.copy(input, os);
                    } catch (Exception e) {
                        throw new IllegalArgumentException(\"Invalid file: \" + e, e);
                    }

                    multipartFile = new CommonsMultipartFile(fileItem);

                    System.out.println(multipartFile);
                     Responsev1 response = modellibFeignClient.saveBackFile(\"lq\", \"zwr\", \"zhh\", \"zhh1\", multipartFile);

完全照此步骤操作，可保证FeignClient上传MultipartFile成功！

至此完成！