如何使用Hibernate Validator动态解析消息参数？

Z时代
2024-01-10
分类：问答

我正在使用Hibernate Validator，并且想在错误消息中解析类别的名称。考虑以下简单情况：

public class Category {
    private String name;
}
public class Product {
    @HazardousCategoryConstraint(message = "{haz.cat.error}")
    private Category category;
    private String name;
}
public class InventoryReport {
    @Valid
    private List<Product> products;
}
ValidationMessages.properties
haz.cat.error={name} is a product in the hazardous category list.

假设我有一个HazardousCategoryConstraint的有效实现。验证器根据受限名称列表检查每个类别的名称。当我调用validate（InventoryReport）时，我得到了我期望的错误数量，但它们是相同的字符串。我希望看到类别名称解析为每条消息。有人可以给我指出一个如何动态解析参数的示例，或向我展示如何进行解析吗？

回答：

IMO，简单的解决方案是创建的自定义实现javax.validation.MessageInterpolator。将主要工作委托给Hibernate

Validator

ResourceBundleMessageInterpolator，并在中进行所需的替换工作CustomMessageInterpolator。

public class CustomMessageInterpolator extends org.hibernate.validator.messageinterpolation.ResourceBundleMessageInterpolator {
    private static final Pattern MESSAGE_PARAMETER_PATTERN = Pattern.compile( "(\\{[^\\}]+?\\})" );
    @Override
    public String interpolate(String message, Context context) {
        String resolvedMessage = super.interpolate(message, context);
        resolvedMessage = replacePropertyNameWithPropertyValues(resolvedMessage, context.getValidatedValue());
        return resolvedMessage;
    }
    private String replacePropertyNameWithPropertyValues(String resolvedMessage, Object validatedValue) {
        Matcher matcher = MESSAGE_PARAMETER_PATTERN.matcher( resolvedMessage );
        StringBuffer sb = new StringBuffer();
        while ( matcher.find() ) {
            String parameter = matcher.group( 1 );
            String propertyName = parameter.replace("{", "");
            propertyName = propertyName.replace("}", "");
            PropertyDescriptor desc = null;
            try {
                desc = new PropertyDescriptor(propertyName, validatedValue.getClass());
            } catch (IntrospectionException ignore) {
                matcher.appendReplacement( sb, parameter );
                continue;
            }
            try {
                Object propertyValue = desc.getReadMethod().invoke(validatedValue);
                matcher.appendReplacement( sb, propertyValue.toString() );
            } catch (Exception ignore) {
                matcher.appendReplacement( sb, parameter );
            }
        }
        matcher.appendTail( sb );
        return sb.toString();
    }
}

public void validate() {
        Configuration<?> configuration = Validation.byDefaultProvider().configure();
        ValidatorFactory validatorFactory = configuration.messageInterpolator(new CustomMessageInterpolator()).buildValidatorFactory();
        Validator validator = validatorFactory.getValidator();
        Product p = new Product();
        Category cat = new Category();
        cat.setName("s"); //assume specified name is invalid
        p.setCategory(cat);
        Set<ConstraintViolation<Product>> violations = validator.validate(p);
        for(ConstraintViolation<Product> violation : violations) {
            System.out.println(violation.getMessage());
        }
    }