GSON: Expected a string but was BEGIN_OBJECT?

user_919716 0
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I'm trying to use GSON to parse some very simple JSON. Here's my code:

    Gson gson = new Gson();

    InputStreamReader reader = new InputStreamReader(getJsonData(url));
    String key = gson.fromJson(reader, String.class);

Here's the JSON returned from the url:

{
  "access_token": "abcdefgh"
}

I'm getting this exception:

E/AndroidRuntime(19447): com.google.gson.JsonSyntaxException:     java.lang.IllegalStateException: Expected a string but was BEGIN_OBJECT at line 1 column 2

Any ideas? I'm new to GSON.

gson android json
3 Answers

Another "low level" possibility using the Gson JsonParser:

package stackoverflow.questions.q11571412;

import com.google.gson.*;

public class GsonFooWithParser
{
  public static void main(String[] args)
  {
    String jsonInput = "{\"access_token\": \"abcdefgh\"}";

    JsonElement je = new JsonParser().parse(jsonInput);

    String value = je.getAsJsonObject().get("access_token").getAsString();
    System.out.println(value);
  }
}

If one day you'll write a custom deserializer, JsonElement will be your best friend.

user_13608880

This is normal parsing exception occurred when Pojo key data type is different from json response

This is due to data type mismatch in Pojo class and actually data which comes in the Network api Response

Eg

data class ProcessResponse(
        val outputParameters: String,
        val pId: Int 
    )

got the same error due to api gives response as

 {
        "pId": 1",
        "outputParameters": {
          "": ""
        }
    }

Here POJO is outputParameters is String but as per api response its json

user_68770570
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