java-gson-json.md

Tags: json|android|gson|java Date: 2012-11-23 16:13:11 -0500 Author: Denevell

First download Google's Gson.

This example will simply convert some JSON into a an object, where the JSON's properties equal the fields in the object:

 public class Example {
    private String text;
    public String getText() {
      return text;
    }
    public void setText(String text) {
      this.text = text;
    }
  }

 new Gson().fromJson("{'text':'text'}", Example.class);

To do the same this with arrays, just pass in a JSON array and set the class type to be an array (I used a traditional Example[] object).

To create custom mappings between JSON properties and object class fields, you need to register a type adapter:

  public class OtherExample {
    private String other;
    public String getOther() {
      return other;
    }
    public void setText(String other) {
      this.other = other;
    }
  }
  
  public class JsonAdapter implements JsonDeserializer<OtherExample> {
    @Override
    public OtherExample deserialize(JsonElement json, Type typeOfT,
                                JsonDeserializationContext context)
                                throws JsonParseException {
      //parse the JsonElement here and return your OtherExample object
      }
  }
  
  Gson gson = new GsonBuilder()
              .registerTypeAdapter(OtherExample.class,
                                   new JsonAdapter()).create();
  gson.fromJson("{'text':'text'}", OtherExample.class);