java - 如何在 android 中解码 JWT token ？

Question

我有一个像这样的 jwt token

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9.TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ

我怎样才能解码这个，这样我才能得到这样的有效载荷

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

我使用过 this 库，但找不到一种方法来做我想做的事

Answer 1

你应该拆分字符串:如果您通过 base 64 解码器传递前两个部分，您将得到以下内容(为清晰起见添加了格式):

标题

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

body

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

代码示例:

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");
    }
}

调用方法举例<​​/p>

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

库引用: https://github.com/jwtk/jjwt

jwt 测试: https://jwt.io/