source: src/main/java/com/example/task/security/CustomAuthenticationSuccessHandler.java

package com.example.task.security;


import com.example.task.entity.StudentEntity;
import com.example.task.repository.StudentRepository;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.AllArgsConstructor;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.web.authentication.AuthenticationSuccessHandler;
import org.springframework.stereotype.Component;

import java.io.IOException;

@Component
@AllArgsConstructor
public class CustomAuthenticationSuccessHandler implements AuthenticationSuccessHandler {

    private final StudentRepository studentRepository;


    @Override
    public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response, Authentication authentication) throws IOException, ServletException {
        UserDetails userDetails = (UserDetails) authentication.getPrincipal();
        try {
            StudentEntity user = studentRepository.findByUsername(userDetails.getUsername()).orElseThrow(Exception::new);
            response.sendRedirect("/");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}