Spring Boot Backend Development Course, Implementing Login and Logout with Spring Security, Implementing Membership Registration

Introduction

Spring Boot is a powerful backend development tool based on the Spring Framework.
With Spring Boot, you can rapidly build applications and receive various features
without complex configurations. In this course, you will learn how to implement
login, logout, and sign-up features using Spring Security. This course will be
beneficial for everyone from beginners to intermediate developers.

Overview of Spring Boot and Spring Security

What is Spring Boot?

Spring Boot is a tool that helps you use the Spring Framework easily by
automatically configuring the basic settings. This allows developers to structure
their projects primarily based on annotations without complex XML configurations.
Spring Boot provides various starters that help developers easily add the libraries
and dependencies they need.

What is Spring Security?

Spring Security is a powerful and flexible authentication and authorization framework
designed for securing Spring-based applications. Through this framework, you can
easily implement login, sign-up, and authority checks in your applications.
Spring Security supports various authentication methods (e.g., form-based
login, OAuth2, etc.).

Creating a Project and Adding Dependencies

To create a Spring Boot-based project, please follow these steps.

  1. Create a new project using Spring Initializr:

    Create a Gradle-based project including Web, Spring Security, JPA, and H2 Database.

  2. Add dependencies in build.gradle:

                        dependencies {
                        implementation 'org.springframework.boot:spring-boot-starter-web'
                        implementation 'org.springframework.boot:spring-boot-starter-security'
                        implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
                        implementation 'com.h2database:h2'
                    }

Implementing Sign-Up

To implement the sign-up feature, please follow these steps.

  1. Create User Entity:

                        @Entity
                    public class User {
                        @Id
                        @GeneratedValue(strategy = GenerationType.IDENTITY)
                        private Long id;
                        private String username;
                        private String password;
                        private String email;
                        // getters and setters
                    }
  2. Create User Repository Interface:

                        public interface UserRepository extends JpaRepository {
                        Optional findByUsername(String username);
                    }
  3. Implement Sign-Up Service:

                        @Service
                    public class UserService {
                        @Autowired
                        private UserRepository userRepository;

                        public void registerNewUser(User user) {
                            // Password encryption and user saving logic
                            user.setPassword(passwordEncoder.encode(user.getPassword()));
                            userRepository.save(user);
                        }
                    }

Implementing Login and Logout

To implement the login and logout features, please follow these steps.

  1. Configure Spring Security:

                        @Configuration
                    @EnableWebSecurity
                    public class SecurityConfig extends WebSecurityConfigurerAdapter {
                        @Override
                        protected void configure(HttpSecurity http) throws Exception {
                            http
                                .authorizeRequests()
                                .antMatchers("/register").permitAll() 
                                .anyRequest().authenticated()
                                .and()
                                .formLogin()
                                .loginPage("/login")
                                .permitAll()
                                .and()
                                .logout()
                                .permitAll();
                        }

                        @Bean
                        public PasswordEncoder passwordEncoder() {
                            return new BCryptPasswordEncoder();
                        }
                    }
  2. Implement Login and Sign-Up Controller:

                        @Controller
                    public class AuthController {
                        @Autowired
                        private UserService userService;

                        @GetMapping("/register")
                        public String showRegistrationForm(Model model) {
                            model.addAttribute("user", new User());
                            return "register";
                        }

                        @PostMapping("/register")
                        public String registerUser(@ModelAttribute User user) {
                            userService.registerNewUser(user);
                            return "redirect:/login";
                        }

                        @GetMapping("/login")
                        public String showLoginForm() {
                            return "login";
                        }
                    }

Final Configuration and Testing

After completing the above steps, apply the following configurations and perform testing:

  1. Configuration in application.properties:

                        spring.h2.console.enabled=true
                    spring.datasource.url=jdbc:h2:mem:testdb
                    spring.datasource.driverClassName=org.h2.Driver
                    spring.datasource.username=sa
                    spring.datasource.password=password
  2. Run the Application and Test:

    Run the application, attempt to sign up at /register, and then go to the /login page to test the login process.

Conclusion

So far, we have learned how to implement sign-up and login/logout procedures using
Spring Boot and Spring Security. I hope this course has helped you build a basic
authentication system. The Spring Framework is highly versatile, and you can build
even more complex systems with it. Additionally, considering further security measures
such as JWT (JSON Web Token) authentication can provide great experience.

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