Example of using Spring Security @AuthenticationPrincipal with OAuth2 Log In

AppUserProfile.java

package me.itzg.tryspringbootoauthlogin.security;

public record AppUserProfile(
    String oauthId,
    java.net.URL issuer,
    String name,
    String givenName,
    String familyName,
    String pictureUrl,
    String profileUrl,
    String email
) {
}

ExampleApiController.java

import me.itzg.tryspringbootoauthlogin.security.AppUserProfile;
import me.itzg.tryspringbootoauthlogin.security.CurrentAppUserProfile;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/api")
public class ApiController {
    /**
     *
     * @param user for OAuth2 login it's an {@link org.springframework.security.oauth2.core.oidc.user.OidcUser},
     *             which extends {@link DefaultOAuth2User} (which implements {@link OAuth2User}), implements {@link OidcUser}
     * @return the logged-in user's name
     */
    @GetMapping("/profile")
    public AppUserProfile profileName(@AuthenticationPrincipal OidcUser user) {

        return user != null ?
            new AppUserProfile(
                user.getName(),
                user.getIssuer(),
                user.getFullName(),
                user.getGivenName(),
                user.getFamilyName(),
                user.getPicture(),
                user.getProfile(),
                user.getEmail()
            )
        : null;
    }
}

• https://docs.spring.io/spring-security/reference/servlet/oauth2/login/index.html
• https://docs.spring.io/spring-security/reference/servlet/integrations/mvc.html#mvc-authentication-principal