Get an ID Token from Okta with Spring Boot

application.yml

okta:
  oauth2:
    issuer: https://{yourOktaDomain}/oauth2/default
    client-id: {clientId}
    client-secret: {clientSecret}

idtoken.groovy

@Grab('com.okta.spring:okta-spring-boot-starter:1.0.0')

import org.springframework.security.core.annotation.AuthenticationPrincipal;
import org.springframework.security.oauth2.core.oidc.OidcIdToken;

@RestController
class Application {

  @GetMapping('/')
  String home(@AuthenticationPrincipal(expression = "idToken") OidcIdToken idToken) {
    idToken.getTokenValue()
  }
}

Put both files in the same directory. Install the Spring Boot CLI, then run:

spring run idtoken.groovy

Hit http://localhost:8080 after you start it, it’ll prompt you to log in, then you’ll see the ID token on the resulting screen.