枚举字段的JSR-303 Bean验证

Question

public class TestBean{
   @Pattern(regexp = "A|B") //does not work
   private TestEnum testField;
   //getters + setters
}

enum TestEnum{
  A, B, C, D
}

javax.validation.UnexpectedTypeException: No validator could be found for type: packagename.TestEnum

Answer 1

由于某些原因，不支持枚举，这个限制可以通过一个简单的基于字符串的验证器来处理。

验证器：

/**
 * Validates a given object's String representation to match one of the provided
 * values.
 */
public class ValueValidator implements ConstraintValidator<Value, Object>
{
    /**
     * String array of possible enum values
     */
    private String[] values;

    @Override
    public void initialize(final Value constraintAnnotation)
    {
        this.values = constraintAnnotation.values();
    }

    @Override
    public boolean isValid(final Object value, final ConstraintValidatorContext context)
    {
        return ArrayUtils.contains(this.values, value == null ? null : value.toString());
    }
}

接口：

@Target(value =
{
    ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR, ElementType.PARAMETER
})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy =
{
    ValueValidator.class
})
@Documented
public @interface Value
{
    public String message() default "{package.Value.message}";

    Class<?>[] groups() default
    {};

    Class<? extends Payload>[] payload() default
    {};

    public String[] values() default
    {};
}