特殊情况下需要做转换

1、M转F

File file = new File(path);    FileUtils.copyInputStreamToFile(multipartFile.getInputStream(), file);  

2、F转M

File file = new File("src/test/resources/input.txt");   FileInputStream input = new FileInputStream(file);   MultipartFile multipartFile =new MockMultipartFile("file", file.getName(), "text/plain", IOUtils.toByteArray(input));

3、 所需依赖  

<dependency>     <groupId>commons-io</groupId>     <artifactId>commons-io</artifactId>     <version>2.4</version> </dependency> <dependency>         <groupId>org.springframework</groupId>         <artifactId>spring-test</artifactId>         <version>5.1.5.RELEASE</version> </dependency>