Cadastro de Usuários 01 — Guia Simplificado: CRUD com Spring Boot e H2 (Local)

package br.com.cadastro.usuarios.entity;

import jakarta.persistence.*;
import org.springframework.security.core.GrantedAuthority;

@Entity
@Table(name = "roles")
public class Role implements GrantedAuthority {
    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;

    @Override
    public String getAuthority() {
        return name;
    }
    // Getters e Setters
    public Long getId() { return id; }
    public void setId(Long id) { this.id = id; }
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
}

package br.com.cadastro.usuarios.entity;

import jakarta.persistence.*;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.userdetails.UserDetails;

import java.util.Collection;
import java.util.Set;

@Entity
@Table(name = "users")
public class User implements UserDetails { // UserDetails é do Spring Security
    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false, unique = true)
    private String username;

    @Column(nullable = false)
    private String password;

    @Column(nullable = false, unique = true)
    private String email;

    @ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(name = "user_roles",
            joinColumns = @JoinColumn(name = "user_id"),
            inverseJoinColumns = @JoinColumn(name = "role_id"))
    private Set<Role> roles;

    // Métodos exigidos pelo UserDetails
    @Override public Collection<? extends GrantedAuthority> getAuthorities() { return this.roles; }
    @Override public boolean isAccountNonExpired() { return true; }
    @Override public boolean isAccountNonLocked() { return true; }
    @Override public boolean isCredentialsNonExpired() { return true; }
    @Override public boolean isEnabled() { return true; }

    // Getters e Setters
    public Long getId() { return id; }
    public void setId(Long id) { this.id = id; }
    public String getUsername() { return username; }
    public void setUsername(String username) { this.username = username; }
    public String getPassword() { return password; }
    public void setPassword(String password) { this.password = password; }
    public String getEmail() { return email; }
    public void setEmail(String email) { this.email = email; }
    public Set<Role> getRoles() { return roles; }
    public void setRoles(Set<Role> roles) { this.roles = roles; }
}

package br.com.cadastro.usuarios.repository;

import br.com.cadastro.usuarios.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import java.util.Optional;

public interface UserRepository extends JpaRepository<User, Long> {
    Optional<User> findByUsername(String username);
}

package br.com.cadastro.usuarios.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.security.web.SecurityFilterChain;

@Configuration
@EnableWebSecurity
public class SecurityConfig {

    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http
            .authorizeHttpRequests(authorize -> authorize
                // Permite acesso livre aos arquivos de CSS e JS
                .requestMatchers("/css/**", "/js/**").permitAll()
                // Qualquer outra requisição precisa de autenticação
                .anyRequest().authenticated()
            )
            // Configura o formulário de login
            .formLogin(form -> form
                .loginPage("/login").permitAll() // Diz qual a URL da nossa página de login
                .defaultSuccessUrl("/", true) // Para onde ir após o login com sucesso
            )
            // Configura o logout
            .logout(logout -> logout.logoutSuccessUrl("/login"));

        return http.build();
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
        // Codificador de senhas. Essencial para a segurança.
        return new BCryptPasswordEncoder();
    }
}

package br.com.cadastro.usuarios.service;

import br.com.cadastro.usuarios.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.stereotype.Service;

@Service
public class AuthorizationService implements UserDetailsService {

    @Autowired
    private UserRepository userRepository;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        return userRepository.findByUsername(username)
                .orElseThrow(() -> new UsernameNotFoundException("Usuário não encontrado."));
    }
}

package br.com.cadastro.usuarios.controller;

import br.com.cadastro.usuarios.entity.User;
import br.com.cadastro.usuarios.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;

import java.util.Optional;

@Controller
public class UserController {

    @Autowired
    private UserRepository userRepository;
    
    @Autowired
    private PasswordEncoder passwordEncoder;

    @GetMapping("/")
    public String index(Model model) {
        model.addAttribute("users", userRepository.findAll());
        model.addAttribute("userForm", new User()); // Objeto para o formulário
        return "index";
    }

    @PostMapping("/save")
    public String saveUser(User user) {
        // Codifica a senha antes de salvar
        user.setPassword(passwordEncoder.encode(user.getPassword()));
        userRepository.save(user);
        return "redirect:/"; // Redireciona para a página principal
    }

    @GetMapping("/edit/{id}")
    public String editUser(@PathVariable("id") Long id, Model model) {
        Optional<User> userOpt = userRepository.findById(id);
        if (userOpt.isEmpty()) {
            return "redirect:/"; // Se não achar, volta para o início
        }
        model.addAttribute("users", userRepository.findAll());
        model.addAttribute("userForm", userOpt.get());
        return "index"; // Reutiliza a mesma página, mas com o formulário preenchido
    }

    @GetMapping("/delete/{id}")
    public String deleteUser(@PathVariable("id") Long id) {
        userRepository.deleteById(id);
        return "redirect:/";
    }
    
    @GetMapping("/login")
    public String login() {
        return "login";
    }
}

package br.com.cadastro.usuarios.config;

import br.com.cadastro.usuarios.entity.User;
import br.com.cadastro.usuarios.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.crypto.password.PasswordEncoder;

@Configuration
public class DataInitializer {

    @Autowired
    private UserRepository userRepository;

    @Autowired
    private PasswordEncoder passwordEncoder;

    @Bean
    public CommandLineRunner initData() {
        return args -> {
            // Cria o usuário admin apenas se ele não existir
            if (userRepository.findByUsername("admin").isEmpty()) {
                User admin = new User();
                admin.setUsername("admin");
                admin.setPassword(passwordEncoder.encode("admin"));
                admin.setEmail("admin@email.com");
                // Aqui você poderia criar e associar roles (perfis)
                userRepository.save(admin);
                System.out.println(">>> Usuário 'admin' criado com senha 'admin'");
            }
        };
    }
}