java - @Valid 在 dropwizard API 资源中有效

Question

我尝试在 API 使用对象之前在 dropwizard 中使用 @Valid。但是，对象的任何属性都没有得到验证，因为似乎验证没有发生？我在添加配置来启用它时是否遗漏了某些内容？

仅供引用:我们已经实现了自己的消息正文读取器，该读取器从 javax.ws.rs.ext.MessageBodyReader 扩展，用于将 JSON 映射到对象。

Answer 1

您需要在 MessageBodyReader 中存储 javax.validation.Validator 对象，并使用它来验证 readFrom() 方法中用 @Valid 注释的类。这就是 Dropwizard 的 Jackson Provider 的做法。

所以代码看起来像这样:

private static final Class<?>[] DEFAULT_GROUP_ARRAY = new Class<?>[]{ Default.class };
private final XmlMapper mapper;
private final Validator validator;

public MyMessageBodyReader(XmlMapper mapper, Validator validator) {
    this.validator = validator;
    this.mapper = mapper;
    setMapper(mapper);
}

@Override
public Object readFrom(Class<Object> type,
                       Type genericType,
                       Annotation[] annotations,
                       MediaType mediaType,
                       MultivaluedMap<String, String> httpHeaders,
                       InputStream entityStream) throws IOException {
    return validate(annotations, super.readFrom(type,
            genericType,
            annotations,
            mediaType,
            httpHeaders,
            entityStream));
}

private Object validate(Annotation[] annotations, Object value) {
    final Class<?>[] classes = findValidationGroups(annotations);

    if (classes != null) {
        final Set<ConstraintViolation<Object>> violations = validator.validate(value, classes);
        if (!violations.isEmpty()) {
            throw new ConstraintViolationException("The request entity had the following errors:",
                    ConstraintViolations.copyOf(violations));
        }
    }

    return value;
}

private Class<?>[] findValidationGroups(Annotation[] annotations) {
    for (Annotation annotation : annotations) {
        if (annotation.annotationType() == Valid.class) {
            return DEFAULT_GROUP_ARRAY;
        } else if (annotation.annotationType() == Validated.class) {
            return  ((Validated) annotation).value();
        }
    }
    return null;
}

我有一个例子here ，我在其中编写了一个具有验证支持的自定义 XML Jackson Reader + Writer。