SpringBoot 上传文件判空以及格式检验

基于jsr303 通过自定义注解实现，实现思路：

存在一些瑕疵，后续补充完善。

部分版本已不默认自动引入该依赖，选择手动引入

        
            org.springframework.boot
            spring-boot-starter-validation
        

目录结构：

• FileNotEmpty 自定义注解
• FileNotEmptyValidator 单文件校验
• FilesNotEmptyValidator 多文件校验

@documented
@Constraint(
        validatedBy = {FileNotEmptyValidator.class, FilesNotEmptyValidator.class}
)
@Target({ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR, ElementType.PARAMETER, ElementType.TYPE_USE})
@Retention(RetentionPolicy.RUNTIME)
public @interface FileNotEmpty {
    
    String message() default "文件格式不正确";

    
    Class[] groups() default {};

    
    Class[] payload() default {};

    
    String[] format() default {};

    
    boolean required() default true;

public class FileNotEmptyValidator implements ConstraintValidator {

    private Set formatSet = new HashSet<>();
    private boolean required;


    @Override
    public void initialize(FileNotEmpty constraintAnnotation) {
        String[] format = constraintAnnotation.format();
        this.formatSet = new HashSet<>(Arrays.asList(format));
        this.required = constraintAnnotation.required();
    }

    @Override
    public boolean isValid(MultipartFile multipartFile, ConstraintValidatorContext constraintValidatorContext) {

        if (multipartFile == null || multipartFile.isEmpty()) {
            return !required;
        }

        String originalFilename = multipartFile.getOriginalFilename();
        assert originalFilename != null;
        String type = originalFilename.substring(originalFilename.lastIndexOf('.') + 1).toLowerCase();
        if (!formatSet.isEmpty()) {
            return formatSet.contains(type);
        }


        return true;
    }
}

public class FilesNotEmptyValidator implements ConstraintValidator {

    private Set formatSet = new HashSet<>();
    private boolean required;

    @Override
    public void initialize(FileNotEmpty constraintAnnotation) {
        String[] format = constraintAnnotation.format();
        this.formatSet = new HashSet<>(Arrays.asList(format));
        this.required = constraintAnnotation.required();
    }

    @Override
    public boolean isValid(MultipartFile[] multipartFiles, ConstraintValidatorContext constraintValidatorContext) {
        if (multipartFiles == null || multipartFiles.length == 0) {
            return !required;
        }

        for (MultipartFile file : multipartFiles) {
            String originalFilename = file.getOriginalFilename();
            assert originalFilename != null;
            String type = originalFilename.substring(originalFilename.lastIndexOf('.') + 1).toLowerCase();
            if (formatSet.isEmpty() || !formatSet.contains(type)) {
                return false;
            }
        }


        return true;
    }
}

@ControllerAdvice
public class ExceptionHandle {
    private final static Logger logger = LoggerFactory.getLogger(ExceptionHandle.class);
       
    @ExceptionHandler(value = Exception.class)
    @ResponseBody
    public Result handle(Exception e) {
        logger.error(e.getMessage());
        StringBuilder stringBuilder = new StringBuilder();             
            //jsr303异常
          if (e instanceof ConstraintViolationException) {
            ConstraintViolationException ex = (ConstraintViolationException)e;
            Set> constraintViolations = ex.getConstraintViolations();
            for (ConstraintViolation constraintViolation : constraintViolations) {
                stringBuilder.append(constraintViolation.getMessageTemplate());
            }
        } else if (e instanceof BindException) {
            BindException bindException = (BindException)e;
            stringBuilder.append(bindException.getFieldErrors()
                .stream()
                .map(FieldError::getDefaultMessage)
                .collect(Collectors.joining(",")));
        } else {
            stringBuilder.append("未知错误:").append("请联系后台运维人员检查处理！");           
        }
        return  ResultUtil.fail(stringBuilder.toString());
    }
    
}

@RestController
@Validated
@RequestMapping("/annex")
public class AnnexController {
 @Resource
 private IAnnexService annexService;

   
    @PostMapping(value = "/upload1")
    public Result upload(@Valid AnnexUploadDTO uploadDTO) {

        return Boolean.TRUE.equals(annexService.upload(uploadDTO)) ? ResultUtil.success() : ResultUtil.fail();
        
    }
    
   
    @PostMapping(value = "/upload2")
    public Result upload(@NotBlank(@FileNotEmpty(format = {"png", "jpg"}, message = "图片为png/jpg格式", required = false)
                                         MultipartFile pictureFile, @FileNotEmpty(format = {"doc", "docx", "xls", "xlsx"}, message = "附件为doc/docx/xls/xlsx格式", required = false)
                                         MultipartFile annexFile) {       
        return Boolean.TRUE.equals(annexService.upload( pictureFile, annexFile)) ? ResultUtil.success() : ResultUtil.fail();
    }
    
	@Data
	static class AnnexUploadDTO{ 
	    @FileNotEmpty(format = {"pdf","doc","zip"}, message = "文件为pdf/doc/zip格式")
	    private MultipartFile[] file;
    }
}