一、MockMultipartFile（org.springframework.mock.web.MockMultipartFile)

 
File file = new File("/Library/d7ca8dd1c3bebdf26a2c8f103cfbd901.jpg");
        FileInputStream inputStream = new FileInputStream(file);
        MultipartFile multipartFile = new MockMultipartFile(file.getName(), file.getName(),
                                                            ContentType.APPLICATION_OCTET_STREAM.toString(), inputStream);

二、commons-fileupload-1.3.2.jar

 File file = new File(/Library/test.txt)
 FileItemFactory factory = new DiskFileItemFactory(16, null);
 FileItem item=factory.createItem(file.getName(),"text/plain",true,file.getName());
 MultipartFile multipartFile = new CommonsMultipartFile(item);