将Jackson与JSON反序列化为多态类型 - 一个完整的例子给我一个编译错误(Deserialize JSON with Jackson into Polymorphic Types - A Complete Example is giving me a compile error)

 我试图通过一个来自程序员布鲁斯的教程来解决多态JSON的反序列化问题。 
 
 完整的列表可以在这里找到程序员布鲁斯教程 （伟大的东西btw） 
 
 我已经完成了前五项任务，但没有遇到任何问题，但最后一项（例6）遇到了困难，这当然是我真正需要的工作。 
 
 我在编译时遇到以下错误 
 
 
 
 ObjectMapper类型中的readValue（JsonParser，Class）方法不适用于参数（ObjectNode，Class） 
 
 
 这是由大量的代码引起的 
 
  public Animal deserialize(  
      JsonParser jp, DeserializationContext ctxt)   
      throws IOException, JsonProcessingException  
  {  
    ObjectMapper mapper = (ObjectMapper) jp.getCodec();  
    ObjectNode root = (ObjectNode) mapper.readTree(jp);  
    Class<? extends Animal> animalClass = null;  
    Iterator<Entry<String, JsonNode>> elementsIterator =   
        root.getFields();  
    while (elementsIterator.hasNext())  
    {  
      Entry<String, JsonNode> element=elementsIterator.next();  
      String name = element.getKey();  
      if (registry.containsKey(name))  
      {  
        animalClass = registry.get(name);  
        break;  
      }  
    }  
    if (animalClass == null) return null;  
    return mapper.readValue(root, animalClass);
  }  
} 
 
 具体由行 
 
 
 
 返回mapper.readValue（root，animalClass）; 
 
 
 有没有人遇到过，如果是这样，有没有解决方案？ 
 
 我会很感激任何人都可以提前致谢Jon D. 

I am attempting to work through a tutorial from Programmer Bruce that is supposed to allow the deserialization of polymorphic JSON. 
 
The complete list can be found here Programmer Bruce tutorials (Great stuff btw)
 
I have worked through the first five with no problems but I have hit a snag on the last one (Example 6), which of course is the one I really need to get working.
 
I am getting the following error at compile time
 
 
 
The method readValue(JsonParser, Class) in the type ObjectMapper is not applicable for the arguments (ObjectNode, Class)
 
 
and it's being caused by the chunk of code
 
  public Animal deserialize(  
      JsonParser jp, DeserializationContext ctxt)   
      throws IOException, JsonProcessingException  
  {  
    ObjectMapper mapper = (ObjectMapper) jp.getCodec();  
    ObjectNode root = (ObjectNode) mapper.readTree(jp);  
    Class<? extends Animal> animalClass = null;  
    Iterator<Entry<String, JsonNode>> elementsIterator =   
        root.getFields();  
    while (elementsIterator.hasNext())  
    {  
      Entry<String, JsonNode> element=elementsIterator.next();  
      String name = element.getKey();  
      if (registry.containsKey(name))  
      {  
        animalClass = registry.get(name);  
        break;  
      }  
    }  
    if (animalClass == null) return null;  
    return mapper.readValue(root, animalClass);
  }  
} 
 
Specifically by the line 
 
 
 
return mapper.readValue(root, animalClass);
 
 
Has anyone run into this before and if so, was there a solution?
 
I'd appreciate any help anyone can give Thanks in advance Jon D.

原文：https://stackoverflow.com/questions/30362446