java中File与MultipartFile互转代码示例

<!--File转MultipartFile需要test包-->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-test</artifactId>
			<version>5.1.9.RELEASE</version>
			<scope>compile</scope>
		</dependency>

    public static File convert(MultipartFile file) throws IOException {
        File convFile = new File(file.getOriginalFilename());
        convFile.createNewFile();
        FileOutputStream fos = new FileOutputStream(convFile);
        fos.write(file.getBytes());
        fos.close();
        return convFile;
    }

//file 转换为 MultipartFile
    private  MultipartFile getMulFileByPath(String filePath)
    {
        FileItemFactory factory = new DiskFileItemFactory(16, null);
        String textFieldName = "textField";
        int num = filePath.lastIndexOf(".");
        String extFile = filePath.substring(num);
        FileItem item = factory.createItem(textFieldName, "text/plain", true,
                "MyFileName" + extFile);
        File newfile = new File(filePath);
        int bytesRead = 0;
        byte[] buffer = new byte[8192];
        try
        {
            FileInputStream fis = new FileInputStream(newfile);
            OutputStream os = item.getOutputStream();
            while ((bytesRead = fis.read(buffer, 0, 8192))
                    != -1)
            {
                os.write(buffer, 0, bytesRead);
            }
            os.close();
            fis.close();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
 
        MultipartFile mfile = new CommonsMultipartFile(item);
        return mfile;
    }