SpringBoot上传和下载文件的原理解析

public class WebConfiguration implements WebMvcConfigurer {

}

addResourceHandlers(ResourceHandlerRegistry registry)

  public static final String FILE_ATTACHMENT_SAVE_ROOT = "/root/**/";
    public static final String ORIGINAL_ATTACHMENT_ADDRESS = "/files/**";

 @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {      
registry.addResourceHandler(ORIGINAL_ATTACHMENT_ADDRESS).addResourceLocations("file:" + FILE_ATTACHMENT_SAVE_ROOT);
    }

public ResponseMessage releaseBlog( @RequestParam(value = "attachments", required = false) MultipartFile[] attachments) throws IOException {
        if (attachments != null) {
            for (MultipartFile attachment : attachments) {
                File file = new File((WebConfiguration.FILE_ATTACHMENT_SAVE_ROOT + UUID.randomUUID() + attachment.getOriginalFilename()).replace("-", ""));
                try {
                    attachment.transferTo(file);
                } catch (IOException e) {
                    if (file.exists()) {
                        file.delete();
                    }
                    e.printStackTrace();
                    throw new BaseException(ExceptionInfo.UPLOAD_ATTACHMENT);
                }
            }
        }
}