How can I decode JWT token in android?

Question

I have a jwt token like this

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9.TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ 

How can I decode this so that I can get the payload like this

{   "sub": "1234567890",   "name": "John Doe",   "admin": true } 

I have used this library , but can't find a way to do what I want

Answer 1

you should split string: If you pass the first two sections through a base 64 decoder, you'll get the following (formatting added for clarity):

header

{   "alg": "HS256",   "typ": "JWT" } 

body

    {   "sub": "1234567890",   "name": "John Doe",   "admin": true } 

Code example:

public class JWTUtils {      public static void decoded(String JWTEncoded) throws Exception {         try {             String[] split = JWTEncoded.split("\\.");             Log.d("JWT_DECODED", "Header: " + getJson(split[0]));             Log.d("JWT_DECODED", "Body: " + getJson(split[1]));         } catch (UnsupportedEncodingException e) {             //Error         }     }      private static String getJson(String strEncoded) throws UnsupportedEncodingException{         byte[] decodedBytes = Base64.decode(strEncoded, Base64.URL_SAFE);         return new String(decodedBytes, "UTF-8");     } } 

Call method for example

JWTUtils.decoded("eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9.TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ"); 

library reference: https://github.com/jwtk/jjwt

jwt test: https://jwt.io/