沒有為列舉springbootjava8的自定義注釋和驗證找到驗證器

收到此錯誤HV000030: No validator could be found for constraint EnumChecker validating type MyEnum Check configuration for ‘myenum’。

使用該類上的注釋進行驗證，我不能這樣做，private final String myenum因為我需要將其用作列舉才能使用列舉內部的函式

public class Request {
     @EnumChecker(enumclass = MyEnum.class)
     private final MyEnum myenum;
}

注解

@Documented
@Constraint(validatedBy = MyEnumValidator.class)
@Target({FIELD, PARAMETER, TYPE, TYPE_USE, TYPE_PARAMETER, METHOD, CONSTRUCTOR, ANNOTATION_TYPE})
@Retention(RUNTIME)
public @interface EnumChecker {
  String message() default "must be one of these values";
  Class<?>[] groups() default {};
  Class<? extends Payload>[] payload() default {};
  Class<? extends Enum> enumClass();
}

驗證器

public class MyEnumValidator implements ConstraintValidator<EnumChecker, String> {
  private List<String> validEnumList;

  @Override
  public void initialize(EnumChecker constraintAnnotation) {
    validEnumList = Arrays.stream(constraintAnnotation.enumClass().getEnumConstants())
        .map(Enum::name)
        .collect(Collectors.toList());
  }

  @Override
  public boolean isValid(String value, ConstraintValidatorContext context) {
    return validEnumList.contains(value);
  }
}

列舉

public enum MyEnum {

  YES, NO;

  private static final Map<MyEnum, String> MyEnumConverter =
      Map.of(YES, "yes");

  public String toMyString() {
    return MyEnumConverter.get(this);
  }

}

uj5u.com熱心網友回復：

首先洗掉final修飾符myenum并為該欄位創建setter和getter，因為例如Jackson無法將http請求中的值系結到您的Request類。

public class Request {
  @EnumChecker(enumClass = MyEnum.class)
  private MyEnum myenum;
  
  public MyEnum getMyenum() {
    return myenum;
  }
  
  public void setMyenum(MyEnum myenum) {
    this.myenum = myenum;
  }
}

然后將ConstraintValidator目標型別更改為匹配MyEnum而不是String

public class MyEnumValidator implements ConstraintValidator<EnumChecker, MyEnum> {

  private List<MyEnum> validEnumList;

  @Override
  public void initialize(EnumChecker constraintAnnotation) {
    validEnumList = Arrays.stream(constraintAnnotation.enumClass().getEnumConstants())
        .collect(Collectors.toList());
  }
  @Override
  public boolean isValid(MyEnum value, ConstraintValidatorContext context) {
    return validEnumList.contains(value);
  }
}

測驗：我做了以下測驗

@RestController
public class MainController {

  @PostMapping("/annot")
  public String filter(@RequestBody @Valid Request req) {
    return req.getMyenum().name();
  }
}

此外，我將實作更改MyEnumValidator為僅查看驗證效果并證明其發生。（我承認目前這個驗證器沒有意義。也只使用只能 擁有或值@RequestBody的保證，否則會引發例外）myenumYESNO

public class MyEnumValidator implements ConstraintValidator<EnumChecker, MyEnum> {

  private List<MyEnum> validEnumList;

  @Override
  public void initialize(EnumChecker constraintAnnotation) {
    validEnumList = Arrays.stream(constraintAnnotation.enumClass().getEnumConstants())
        .collect(Collectors.toList());
  }
  @Override
  public boolean isValid(MyEnum value, ConstraintValidatorContext context) {
    return validEnumList.contains(value) && value.name().length() == 3;
  }
}

對于無效的情況：

堆疊跟蹤：

Resolved [org.springframework.web.bind.MethodArgumentNotValidException: Validation failed for argument [0] in public java.lang.String api.sweater.controller.MainController.filter(api.sweater.request.Request): [Field error in object 'request' on field 'myenum': rejected value [NO]; codes [EnumChecker.request.myenum,EnumChecker.myenum,EnumChecker.api.sweater.request.MyEnum,EnumChecker]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [request.myenum,myenum]; arguments []; default message [myenum],class api.sweater.request.MyEnum]; default message [must be one of these values]] ]

標籤：春天 弹簧靴 弹簧MVC java-8 注释

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