如题，本篇我们介绍下springcloud中如何使用feign进行文件上传与下载。 

一、Feign文件上传

服务提供方java代码： 

	/**
	 * 文件上传 
	 * @param file 文件  
	 * @param fileType    
	 * @return
	 */
	@RequestMapping(method = RequestMethod.POST, value = "/uploadFile",
            produces = {MediaType.APPLICATION_JSON_UTF8_VALUE},
            consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
    public String uploadFile(@RequestPart(value = "file") MultipartFile file,
    		@RequestParam(value = "fileType") String fileType,
    		HttpServletRequest request,HttpServletResponse response) {
		System.out.println("fileType:"+fileType);
		long size= file.getSize();
		String contentType= file.getContentType();
		String name = file.getName();
		String orgFilename= file.getOriginalFilename();
		
		 
		
		System.out.println("size:"+size);
		System.out.println("contentType:"+contentType);
		System.out.println("name:"+name);
		System.out.println("orgFilename:"+orgFilename);
		
		String suffix = orgFilename.substring(orgFilename.lastIndexOf("."));//后缀
		 
		String uuid =UUID.randomUUID().toString().replaceAll("-", "").toUpperCase();
		
		File dest =   new File("f:/b13/"+uuid+suffix);
		 try {
			file.transferTo(dest);
			
			return dest.getCanonicalPath();//文件的绝对路径
		} catch (IllegalStateException | IOException e) {
			e.printStackTrace();
		}
		 return "failure";
	}

服务提供方Feign api接口：

@RequestMapping(method = RequestMethod.POST, value = "/uploadFile",
            produces = {MediaType.APPLICATION_JSON_UTF8_VALUE},
            consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
    public String uploadFile(@RequestPart(value = "file") MultipartFile file, @RequestParam(value = "fileType") String fileType);

服务消费方：

pom.xml 

<!--  引入文件feign文件上传依赖 -->
    <dependency>
       <groupId>io.github.openfeign.form</groupId>
       <artifactId>feign-form</artifactId>
       <version>3.0.3</version>
     </dependency>
    <dependency>
       <groupId>io.github.openfeign.form</groupId>
       <artifactId>feign-form-spring</artifactId>
       <version>3.0.3</version>
    </dependency>

java代码

   @Autowired
private UserProControllerApi   userProControllerApi;
 
 
 @ResponseBody
 @RequestMapping("/user_uploadFile")
 public Object  user_uploadFile(HttpServletRequest request,HttpServletResponse response,
         @RequestPart(value = "file") MultipartFile file, String fileType) {
   
       System.out.println(fileType);
       
      return userProControllerApi.uploadFile(file, fileType);
 }

FeignMultipartSupportConfig .java

@Configuration
public class MultipartSupportConfig {
	
    
    @Autowired
    private ObjectFactory<HttpMessageConverters> messageConverters;
    

    @Bean
    @Primary
    @Scope("prototype")
    public Encoder feignEncoder() {
          return new SpringFormEncoder(new SpringEncoder(messageConverters));
    }
    
     @Bean
	  public feign.Logger.Level multipartLoggerLevel() {
	      return feign.Logger.Level.FULL;
	  }

}

二、Feign文件下载

服务提供方java代码：

 /**
	   * 文件（二进制数据）下载 
	   * @param fileType 文件类型
	   * @return
	   */
	  @RequestMapping("/downloadFile")
	  public   ResponseEntity downloadFile(String fileType,HttpServletRequest request ){
		  
		   System.out.println(request.getParameter("fileType"));
		   System.out.println("参数fileType: "+fileType);
		  
		  HttpHeaders headers = new HttpHeaders();
		  ResponseEntity entity = null;
		  InputStream in=null;
		   try {
			in=new FileInputStream(new File("d:/myImg/001.png"));
			 
			byte[] bytes = new byte[in.available()];
			 
			String imageName="001.png";
			
			//处理IE下载文件的中文名称乱码的问题
    		String header = request.getHeader("User-Agent").toUpperCase();
            if (header.contains("MSIE") || header.contains("TRIDENT") || header.contains("EDGE")) {
            	imageName = URLEncoder.encode(imageName, "utf-8");
            	imageName = imageName.replace("+", "%20");    //IE下载文件名空格变+号问题
            } else {
            	imageName = new String(imageName.getBytes(), "iso-8859-1");
            }
			 
			in.read(bytes);
			
			headers.add("Content-Disposition", "attachment;filename="+imageName);
			 
			entity = new ResponseEntity(bytes, headers, HttpStatus.OK);
			
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			if(in!=null) {
				try {
					in.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		 
		   return entity;
	  }

服务提供方feign api接口

@RequestMapping("/downloadFile")
	  public   ResponseEntity downloadFile(@RequestParam(value = "fileType")  String fileType
			  );

服务消费方:

@ResponseBody 
	 @RequestMapping("/user_downloadFile")
	 public Object  user_downloadFile(HttpServletRequest request,HttpServletResponse response,
			  String fileType) {
		 ResponseEntity  entity = userProControllerApi.downloadFile(fileType);
		 System.out.println( entity.getStatusCode());
		 return entity ;
	 }

注：实际项目中如果上传的文件太大，可以使用ftp服务器保存上传的文件，直接在controller端调用ftp接口即可。

如果下载的文件太大，则调用service端接口可返回一个ftp文件资源路径，然后在controller端调用ftp下载文件即可。