这是我的控制器。它接受带有两个字段multipart/form-dataformfile请求。 form字段是一个MyObjectfile字段是MultipartFile。这两个变量都用@Valid注释,因此,我希望Spring调用每个相应字段的Validator类。但是,这仅发生在MyObject上,而不发生在MultipartFile上。

@RequestMapping("/api")
@RestController
public class Controller {

    private MyObjectRepository repo;
    private MyObjectValidator myObjectValidator;
    private FileValidator fileValidator;

    @Autowired
    public myObjectController(MyObjectRepository repo, MyObjectValidator myObjectValidator,
                              FileValidator fileValidator) {
        this.repo = repo;
        this.myObjectValidator = myObjectValidator;
        this.fileValidator = fileValidator;
    }

    @InitBinder("form")
    public void initMyObjectBinder(WebDataBinder binder) {
        binder.setValidator(this.myObjectValidator);
    }

    @InitBinder("file")
    public void initFileBinder(WebDataBinder binder) {
        binder.setValidator(this.fileValidator);
    }

    @PostMapping("myObject")
    @ResponseStatus(HttpStatus.CREATED)
    @ResponseBody
    public MyObject createMyObject(@RequestPart("form") @Valid MyObject myObject,
                                   @RequestPart("file") @Valid MultipartFile... file) {
        return repo.save(myObject);
    }
}

我的MyObjectValidator已触发,但我的FileValidator未触发。这两个类都实现了Spring Validator接口。 MyObjectValidator.supports(Class<?> aClass)被调用,而FileValidator.supports(Class<?> aClass)从不被调用。除此之外,我的Controller运转良好,并努力地将对象保存到repo

这可能是什么问题?我已经读过类似的问题,常见的错误是不在@InitBinder批注内使用适当的参数,或者将@InitBinder方法设置为private而不是public,但这两种情况均不适用于我的情况。

这种丑陋的解决方法可以实现预期的功能,但它与Spring并不一样。我在FileValidator方法内手动调用了Controller.createMyObject,而不是让Spring通过@Valid批注自动调用它。
@PostMapping("myObject")
@ResponseStatus(HttpStatus.CREATED)
@ResponseBody
public MyObject createMyObject(@RequestPart("form") @Valid MyObject myObject,
                               @RequestPart("file") @Valid MultipartFile... file) {
    if (fileValidator.supports(file.getClass())) {
        Errors errors = new BeanPropertyBindingResult(file, "Uploaded file.");
        fileValidator.validate(file,errors);
        if (errors.hasErrors()) {
            throw new BadRequestException();
        }
    }
    return repo.save(myObject);
}

编辑:我已应要求包括了Validator类。
import org.springframework.validation.Validator;

public abstract class AbstractValidator implements Validator {
    // One shared method here.
}
public class FileValidator extends AbstractValidator {

    public boolean supports(Class<?> aClass) { // This method is never triggered.
        boolean isSingleFile = MultipartFile.class.isAssignableFrom(aClass); // This line has a breakpoint, it is never triggered in the debugger.
        boolean isFileArray = aClass.equals(MultipartFile[].class);
        return (isSingleFile || isFileArray);
    }

    public void validate(Object o, Errors e) {
        //Several validation methods go here.
    }
public class MyObjectValidator extends AbstractValidator {

    public boolean supports(Class<?> aClass) { // This method is triggered.
        return (MyObject.class.equals(aClass)); // This line has a breakpoint, and it is always triggered in the debugger.
    }

    public void validate(Object o, Errors e) {
        // Several validation methods go here.
    }

编辑:我对代码进行了一些更改,如建议的NiVeR,删除了varargs参数,并相应地更改了FileValidator.supports(Class<?> aClass),但是行为仍然相同。

在Controller.java中:
@PostMapping("myObject")
@ResponseStatus(HttpStatus.CREATED)
@ResponseBody
public MyObject createMyObject(@RequestPart("form") @Valid MyObject myObject, @RequestPart("file") @Valid MultipartFile file) {
    return repo.save(myObject);
}

在FileValidator.java中:
public boolean supports(Class<?> aClass) {
    return MultipartFile.class.isAssignableFrom(aClass);
}

最佳答案

我相信问题与可变参数Multipart...参数有关。在验证器的supports方法中,您正在检查Multipart数组,但我怀疑这不是正确的方法。就像试用一样,我将Multipart设为单个对象参数(并相应地更改验证器)以测试其是否以此方式工作。

08-06 20:00