使用Jackson，如何为任意pojo类获取已知JSON属性的列表？ [英] Using Jackson, how can a list of known JSON properties be obtained for any arbitrary pojo class?
问题描述
理想情况下，它看起来很像：
Ideally, it would look much like this:
List<String> props = objectMapper.getKnownProperties(MyPojo.class);
唉，没有这样的方法。通常可行的方法是将Include.ALWAYS显式设置为ObjectMapper的默认值，反射性地实例化该类的实例，将其转换为映射，并检查键集。但是，类仍然可以覆盖给定注释的ObjectMapper的包含行为。
Alas, there is no such method. An approach that would generally work is to explicitly set Include.ALWAYS as the ObjectMapper's default, instantiate an instance of the class reflectively, convert it to a map, and examine the keyset. However, classes can still override the ObjectMapper's include behavior given annotations.
有更优雅的方法吗？至少，有没有办法使用对象映射器覆盖类注释？
Is there a more elegant approach? At the very least, is there a way to override class annotations using the object mapper?
编辑：
澄清一下，这些pojos / javabeans / DTO设计用于与Jackson一起使用，并且已经使用注释进行操作以产生特定的序列化行为。事实上，我需要动态地知道我可能会预先得到什么，最好不要重复杰克逊已有的信息。也就是说，如果另一个框架提供此功能，我很想知道。 :)
Just to clarify, these pojos/javabeans/DTOs are designed for use with Jackson and are already rigged with annotations to result in specific serialization behavior. It just so happens that I need to dynamically know what I might end up with up-front, ideally without duplicating the information already available to jackson. That said, if another framework offers this functionality, I'd be curious to know. :)
推荐答案
使用Jackson，您可以使用以下内容对类进行内省并获取可用的JSON属性：
With Jackson, you can introspect a class and get the available JSON properties using:
// Construct a Jackson JavaType for your class
JavaType javaType = mapper.getTypeFactory().constructType(MyDto.class);
// Introspect the given type
BeanDescription beanDescription = mapper.getSerializationConfig().introspect(javaType);
// Find properties
List<BeanPropertyDefinition> properties = beanDescription.findProperties();
如果您有 @JsonIgnoreProperties 班级注释，检查一下< a href =https://stackoverflow.com/a/45839099/1426227>答案。
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