如何将 @JsonProperty 注释与包含不同格式元素的数组一起使用

Question

I'm using an API that uses in requests & responses json array in a SpringBoot App with elements of various format and I'm struggling to dynamically get the right class to be used for serialisation/deserialisation of elements of such array.

Here is a simplified description of the json:

{
    "parameters" :[
        {
            "name": "elementA",
            "value": "valueOfElementAsAString"
        },
        {
            "name": "elementB",
            "value": "valueOfElementBAsString"
        },
        {
            "name": "elementC",
            "value": [
                {
                    "label":"label1",
                    "size":"size1"
                },
                {
                    "label":"label2",
                    "size":"size2"
                }

            ] 
        }
    ]
}

Considering the following base classes:

class SimpleElement {
    @JsonProperty("name")
    public String name;
    @JsonProperty("value")
    public String value;

    //constructor & stuff 
}


class ComplexElement {
    @JsonProperty("name")
    public String name;
    @JsonProperty("value")
    public ArrayList<ComplexElementValue> value = new ArrayList<ComplexElementValue>();

    //constructor & stuff 
}

class ComplexElementValue {
    @JsonProperty("label")
    public String label;
    @JsonProperty("size")
    public String size;  

    //constructor & stuff   
}

Serialization/Deserialisation of individual Simple or Complex Elements works fine but how shall I declare my class Parameters using @JsonProperty to get the full array correctly handled?:

class Parameters {
    ???
}

Based on what I read, I've got the impression I have to write custom deserialiser & serialiser but before doing so I would like to make sure there is no simpler way?

At the moment, considering I've got nx simpleElements and 1 x complexElement, I get it to work with such a class:

class Parameter {
   @JsonProperty("parameters")
   public MultiElement element;

   public class MultiElement {
      public ArrayList<SimpleElement> regularElements;
      public ComplexElement complexElement;
   }
  
   //constructor & stuff 
}

and handling the deserialisation/serialisation of the json "manually" using a JsonNode library (in this case org.camunda.spin.json.SpinJsonNode), but this sounds for me like a temporary solution

Thanks in advance

Answer 1

For handling dynamic json using jackson.

1. JsonNode is simple one.

   public class Paramter { private List parameters; //Getters and setters public static class Parameters {

    private String name; private JsonNode value; //Getters and setters }

   }

2. this will help you correctly if if need concrete class Jackson - parse different model under same key at runtime

Answer 2

Basically try to convert json to java class using any online converters like http://www.jsonschema2pojo.org/

Try using modelmapper library for object mapping. Like mapping json objects to java objects.