[java] How to convert a String to JsonObject using gson library

Please advice how to convert a String to JsonObject using gson library.

What I unsuccesfully do:

String string = "abcde";
Gson gson = new Gson();
JsonObject json = new JsonObject();
json = gson.toJson(string); // Can't convert String to JsonObject

You don't need to use JsonObject. You should be using Gson to convert to/from JSON strings and your own Java objects.

See the Gson User Guide:

(Serialization)

Gson gson = new Gson();
gson.toJson(1);                   // prints 1
gson.toJson("abcd");              // prints "abcd"
gson.toJson(new Long(10));        // prints 10
int[] values = { 1 };
gson.toJson(values);              // prints [1]

(Deserialization)

int one = gson.fromJson("1", int.class);
Integer one = gson.fromJson("1", Integer.class);
Long one = gson.fromJson("1", Long.class);
Boolean false = gson.fromJson("false", Boolean.class);
String str = gson.fromJson("\"abc\"", String.class);
String anotherStr = gson.fromJson("[\"abc\"]", String.class)

String emailData = {"to": "[email protected]","subject":"User details","body": "The user has completed his training"
}

// Java model class
public class EmailData {
    public String to;
    public String subject;
    public String body;
}

//Final Data
Gson gson = new Gson();  
EmailData emaildata = gson.fromJson(emailData, EmailData.class);

String string = "abcde"; // The String which Need To Be Converted
JsonObject convertedObject = new Gson().fromJson(string, JsonObject.class);

I do this, and it worked.

JsonObject jsonObject = (JsonObject) new JsonParser().parse("YourJsonString");

Looks like the above answer did not answer the question completely.

I think you are looking for something like below:

class TransactionResponse {

   String Success, Message;
   List<Response> Response;

}

TransactionResponse = new Gson().fromJson(response, TransactionResponse.class);

where my response is something like this:

{"Success":false,"Message":"Invalid access token.","Response":null}

As you can see, the variable name should be same as the Json string representation of the key in the key value pair. This will automatically convert your gson string to JsonObject.

Note that as of Gson 2.8.6, instance method JsonParser.parse has been deprecated and replaced by static method JsonParser.parseString:

JsonObject jsonObject = JsonParser.parseString(json).getAsJsonObject();

To do it in a simpler way, consider below:

JsonObject jsonObject = (new JsonParser()).parse(json).getAsJsonObject();

Gson gson = new Gson();
YourClass yourClassObject = new YourClass();
String jsonString = gson.toJson(yourClassObject);