spring boot图片上传

配置限制文件上传大小

 servlet:
    multipart:
      max-file-size: 5MB # 限制文件上传的大小

SpringMVC会封装为一个接口：MultipartFile

@Controller
@RequestMapping("upload")
public class UploadController {

    @Autowired
    private UploadService uploadService;

    /**
     * 图片上传
     * @param file
     * @return
     */
    @PostMapping("image")
    public ResponseEntity<String> uploadImage(@RequestParam("file") MultipartFile file){
        String url = this.uploadService.upload(file);
        if (StringUtils.isBlank(url)) {
            return ResponseEntity.badRequest().build();
        }
        return ResponseEntity.status(HttpStatus.CREATED).body(url);
    }
}

对上传的内容进行校验：

1. 校验文件大小

2. 校验文件的媒体类型

3. 校验文件的内容

@Service
public class UploadService {

    private static final List<String> CONTENT_TYPES = Arrays.asList("image/jpeg", "image/gif");

    private static final Logger LOGGER = LoggerFactory.getLogger(UploadService.class);

    public String upload(MultipartFile file) {

        String originalFilename = file.getOriginalFilename();
        // 校验文件的类型
        String contentType = file.getContentType();
        if (!CONTENT_TYPES.contains(contentType)){
            // 文件类型不合法，直接返回null
            LOGGER.info("文件类型不合法：{}", originalFilename);
            return null;
        }

        try {
            // 校验文件的内容
            BufferedImage bufferedImage = ImageIO.read(file.getInputStream());
            if (bufferedImage == null){
                LOGGER.info("文件内容不合法：{}", originalFilename);
                return null;
            }

            // 保存到服务器
            file.transferTo(new File("C:\test\images\" + originalFilename));

            // 生成url地址，返回
            return "http://image.test.com/" + originalFilename;
        } catch (IOException e) {
            LOGGER.info("服务器内部错误：{}", originalFilename);
            e.printStackTrace();
        }
        return null;
    }
}