Spring验证-类级别验证以解决字段错误 [英] Spring Validation - Class level validation to address field errors

问题描述

如果我们定义一个类级别的验证注释，例如一个比较字段并具有ConstraintValidator这样的注释:

If we define a class level validation annotation, such as one which compare fields and have a ConstraintValidator like this:

public class ComparisonValidator implements ConstraintValidator<ValueMatches, Object>
{
    private String[] fields;

    @Override
    public void initialize(final ValueMatches constraintAnnotation) {
        fields = constraintAnnotation.fields();
    }

    @Override
    public boolean isValid(final Object value, final ConstraintValidatorContext context) {
        if (fields.length == 0) {
            return true;
        }

        final BeanWrapperImpl beanWrapper = new BeanWrapperImpl(value);
        final Object comparisonValue = beanWrapper.getPropertyValue(fields[0]);

        for (int i = 1; i < fields.length; i++) {
            final Object fieldValue = beanWrapper.getPropertyValue(fields[i]);

            if (!comparisonValue.equals(fieldValue)) {
                return false;
            }
        }

        return true;
    }
}

我们很好地产生了一个全局验证错误，可以通过Thymeleaf使用以下方法进行访问: ${#fields.errors('global')}

We well produce a Global validation error, accessible via Thymeleaf using: ${#fields.errors('global')}

现在，我如何识别该错误并了解它是特定的比较错误?我的意思是，毕竟我们会收到有关全局错误的消息，还是我错了?

Now, how can I identify that error and understand it is the specific comparison error? I mean, after all we get a message for global errors, or am I wrong?

推荐答案

该死，Spring文档！ 这很简单，但并不是很容易理解.

Damn you, Spring documentation! It is fairly simple, but not really understandable.

@Override
public boolean isValid(final Object value, final ConstraintValidatorContext context) {
    if (fields.length > 0) {
        final BeanWrapperImpl beanWrapper = new BeanWrapperImpl(value);
        final Object comparisonValue = beanWrapper.getPropertyValue(fields[0]);

        for (int i = 1; i < fields.length; i++) {
            if (!comparisonValue.equals(beanWrapper.getPropertyValue(fields[i]))) {
                context.disableDefaultConstraintViolation();
                context.buildConstraintViolationWithTemplate(errorMessage).addPropertyNode(fields[0]).addConstraintViolation();
                return false;
            }
        }
    }

    return true;
}

方法disableDefaultConstraintViolation()告诉ConstrainValidatorContext通过使用注释本身不产生约束违反对象.

The method disableDefaultConstraintViolation() tells the ConstrainValidatorContext to not produce the constraint violation object by using the annotation itself.

然后您可以通过buildConstraintViolationWithTemplate()方法产生自定义约束违规.

You can then produce a custom constraint violation via the buildConstraintViolationWithTemplate() method.

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