发表新帖
发表新帖

Deserializing an abstract class in Gson

前端 未结
关注
4 1995
盖世英雄少女心
盖世英雄少女心 2020-11-27 16:10

I have a tree object in JSON format I\'m trying to deserialize with Gson. Each node contains its child nodes as fields of object type Node. Node is an interface, which has

4条回答
  • 南笙
    南笙 (楼主)
    2020-11-27 16:47

    You will need to register both JSONSerializer and JSONDeserializer. Also you can implement a generic adapter for all your interfaces in the following way:

    • During Serialization : Add a META-info of the actual impl class type.
    • During DeSerialization : Retrieve that meta info and call the JSONDeserailize of that class

    Here is the implementation that I have used for myself and works fine.

    public class PropertyBasedInterfaceMarshal implements
        JsonSerializer, JsonDeserializer {

    private static final String CLASS_META_KEY = "CLASS_META_KEY";

    @Override
    public Object deserialize(JsonElement jsonElement, Type type,
            JsonDeserializationContext jsonDeserializationContext)
            throws JsonParseException {
        JsonObject jsonObj = jsonElement.getAsJsonObject();
        String className = jsonObj.get(CLASS_META_KEY).getAsString();
        try {
            Class clz = Class.forName(className);
            return jsonDeserializationContext.deserialize(jsonElement, clz);
        } catch (ClassNotFoundException e) {
            throw new JsonParseException(e);
        }
    }

    @Override
    public JsonElement serialize(Object object, Type type,
            JsonSerializationContext jsonSerializationContext) {
        JsonElement jsonEle = jsonSerializationContext.serialize(object, object.getClass());
        jsonEle.getAsJsonObject().addProperty(CLASS_META_KEY,
                object.getClass().getCanonicalName());
        return jsonEle;
    }

}



    Then you could register this adapter for all your interfaces as follows
    


    Gson gson = new GsonBuilder()
        .registerTypeAdapter(IInterfaceOne.class,
                new PropertyBasedInterfaceMarshal())
        .registerTypeAdapter(IInterfaceTwo.class,
                new PropertyBasedInterfaceMarshal()).create();

    
    
    
             
    
                                                        
    
            
            
    
              
                
                0
              
                   
                
               讨论(0)
              
                                                  
              
              
    
                          
             
       
          
              
    
                                       
    

    

                
    
                         
          
                              			
        
        
        
    
          
    
            
            
    
              
              
    
            
    


                                 
              
    
            
    
                          
    

        
         
    
                
                
    
                  
                
    
                
    
                   看不清?
                
    
              
    
                                  
    
                    
   
                 
             
              
    提交回复
    
            
    
          
    
        
    
      
       
      
    
    
    
          
 
     
 
    
        
    热议问题