source: src/main/java/com/example/salonbella/security/CustomSuccessHandler.java

package com.example.salonbella.security;

import org.springframework.context.annotation.Configuration;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.authority.AuthorityUtils;
import org.springframework.security.web.authentication.AuthenticationSuccessHandler;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Set;

@Configuration
public class CustomSuccessHandler implements AuthenticationSuccessHandler {

    @Override
    public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response, Authentication authentication) throws IOException, ServletException {
        Set<String> roles = AuthorityUtils.authorityListToSet(authentication.getAuthorities());

        if (roles.contains("ROLE_ADMIN")) {
            response.sendRedirect("/adminDashboard");
        } else {
            response.sendRedirect("/userDashboard");
        }
    }
}