Google's GSON library to parse JSON

Google's OAuth 2.0 library returns access token related information in JSON format as shown in the sample below:

{
  "access_token":"1/fFAGRNJru1FTz70BzhT3Zg",
  "expires_in":3920,
  "token_type":"Bearer"
}

I was looking for a library to parse JSON and stumbled across GSON, which was very straightforward to use. The library has methods to create a java object from JSON or JSON from a java object. The sample program below shows how to do the former.

Download GSON library from here.

Create a class that can be used to create java objects to hold converted JSON.

public class GoogleAccessToken {




String access_token;

String refresh_token;

String token_type;

int expires_in;




 @Override

 public String toString() {

           return "access_token: " + access_token + "refresh_token: " + refresh_token +" - " + "token_type:"+ token_type + " - " + "expires_in:" + expires_in;

 }




 public String getAccessToken() {

  return access_token;

 }




 public String getRefreshToken() {

  return refresh_token;

 }




 public String getTokenType() {

  return token_type;

 }

 public int getExpiresIn() {

  return expires_in;

 }

}

Assume myJsonString variable has the JSON that needs to be parsed.

Gson gson = new GsonBuilder().create();


GoogleAccessToken jsonObject = gson.fromJson(myJsonString,GoogleAccessToken.class)

Now that the JSON is converted to java object form, you can access it's variables using the accessor functions.

jsonObject.toString()

//the above line prints the following: 

//access_token: 1/fFAGRNJru1FTz70BzhT3Zg refresh_token: - token_type: Bearer - expires_in: 3920