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.

© 2023 Spring Boot Backend Development Course

Spring Boot Backend Development Course, Implementing Login and Logout with Spring Security, User Registration, Creating User Registration and Login Views

스프링 시큐리티로 로그인/로그아웃 및 회원 가입 구현

안녕하세요! 이번 강좌에서는 스프링 부트스프링 시큐리티를 활용하여 기본적인 로그인/로그아웃 기능과 회원 가입 시스템을 구현해 보겠습니다. 이 강좌는 Java와 웹 개발에 대한 기본 지식이 있는 분들을 대상으로 하며, 실용적인 예제를 통해 배우실 수 있습니다.

1. 스프링 부트란?

스프링 부트는 스프링 프레임워크를 기반으로 한 서버측 애플리케이션 개발을 보다 간편하게 해주는 솔루션입니다. 복잡한 XML 설정을 줄이고, ‘Convention over Configuration’ 원칙을 통해 개발자가 비즈니스 로직에 집중할 수 있도록 도와줍니다. 특히, RESTful API 구축과 마이크로서비스 아키텍처에 적합하여 빠른 개발 환경을 제공합니다.

2. 스프링 시큐리티란?

스프링 시큐리티는 스프링 기반 애플리케이션을 위한 인증 및 인가 기능을 제공하는 프레임워크입니다. 유연한 보안 설정과 다양한 인증 방식을 지원하여, 애플리케이션의 보안을 강화하는 데 도움을 줍니다. 비밀번호 암호화, URL 기반 접근 제어, 사용자 역할 및 권한 관리 등의 기능을 제공합니다.

3. 프로젝트 세팅

3.1. 스프링 부트 초기화

스프링 부트 프로젝트를 생성하기 위해, Spring Initializr를 사용합니다. 필요한 의존성(Dependencies)으로는 다음과 같은 것들이 있습니다:

  • Spring Web
  • Spring Security
  • Spring Data JPA
  • H2 Database (또는 MySQL, PostgreSQL 등)
  • Spring Boot DevTools (개발 편의성 향상)

모든 의존성을 추가한 후, ZIP 파일로 프로젝트를 다운로드하고 IDE(예: IntelliJ IDEA, Eclipse)에 임포트합니다.

3.2. 디렉토리 구조 설정

기본 프로젝트 구조는 다음과 같습니다:

    src/
      └── main/
          ├── java/
          │   └── com/
          │       └── example/
          │           └── demo/
          │               ├── controller/
          │               ├── model/
          │               ├── repository/
          │               ├── security/
          │               └── service/
          └── resources/
              ├── application.properties
              └── static/
              └── templates/
    

4. 회원 가입 기능 구현

4.1. 사용자 모델 생성

회원 가입을 위해 사용자 정보를 저장할 User 엔티티 클래스를 생성합니다.

    package com.example.demo.model;

    import javax.persistence.*;
    import java.util.Collection;

    @Entity
    public class User {
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Long id;

        private String username;
        private String password;
        
        @ElementCollection(fetch = FetchType.EAGER)
        private Collection roles;

        // Getters and Setters
    }
    

4.2. 레포지토리 인터페이스 작성

데이터베이스와의 상호작용을 위해 레포지토리 인터페이스를 정의합니다.

    package com.example.demo.repository;

    import com.example.demo.model.User;
    import org.springframework.data.jpa.repository.JpaRepository;

    public interface UserRepository extends JpaRepository {
        User findByUsername(String username);
    }
    

4.3. 서비스 클래스 작성

유저 정보를 처리하는 서비스 클래스를 구현합니다.

    package com.example.demo.service;

    import com.example.demo.model.User;
    import com.example.demo.repository.UserRepository;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
    import org.springframework.stereotype.Service;

    @Service
    public class UserService {

        @Autowired
        private UserRepository userRepository;

        @Autowired
        private BCryptPasswordEncoder passwordEncoder;

        public void registerUser(User user) {
            user.setPassword(passwordEncoder.encode(user.getPassword()));
            userRepository.save(user);
        }

        public User findUserByUsername(String username) {
            return userRepository.findByUsername(username);
        }
    }
    

4.4. 회원 가입 컨트롤러 구현

회원 가입 요청을 처리할 컨트롤러를 만들어야 합니다.

    package com.example.demo.controller;

    import com.example.demo.model.User;
    import com.example.demo.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.Model;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.RequestMapping;

    @Controller
    @RequestMapping("/auth")
    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(User user) {
            userService.registerUser(user);
            return "redirect:/auth/login";
        }
    }
    

4.5. 뷰 템플릿 작성

회원 가입을 위한 Thymeleaf 템플릿을 작성합니다.

    <!-- src/main/resources/templates/register.html -->
    <!DOCTYPE html>
    <html xmlns:th="http://www.thymeleaf.org">
    <head>
        <title>회원 가입</title>
    </head>
    <body>
        <h1>회원 가입</h1>
        <form action="@{/auth/register}" method="post">
            <label for="username">사용자 이름:</label>
            <input type="text" id="username" name="username" required><br>
            <label for="password">비밀번호:</label>
            <input type="password" id="password" name="password" required><br>
            <button type="submit">가입</button>
        </form>
    </body>
    </html>
    

5. 로그인/로그아웃 기능 구현

5.1. 스프링 시큐리티 설정

스프링 시큐리티를 설정하기 위해 다음 클래스를 생성합니다.

    package com.example.demo.security;

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

    @Configuration
    @EnableWebSecurity
    public class SecurityConfig extends WebSecurityConfigurerAdapter {

        @Bean
        public PasswordEncoder passwordEncoder() {
            return new BCryptPasswordEncoder();
        }

        @Override
        protected void configure(AuthenticationManagerBuilder auth) throws Exception {
            auth.userDetailsService(userDetailsService()).passwordEncoder(passwordEncoder());
        }

        @Override
        protected void configure(HttpSecurity http) throws Exception {
            http.csrf().disable()
                .authorizeRequests()
                .antMatchers("/auth/register", "/auth/login").permitAll()
                .anyRequest().authenticated()
                .and()
                .formLogin()
                .loginPage("/auth/login")
                .permitAll()
                .and()
                .logout()
                .permitAll();
        }
    }
    

5.2. 로그인 뷰 작성

로그인 페이지를 위한 Thymeleaf 템플릿을 작성합니다.

    <!-- src/main/resources/templates/login.html -->
    <!DOCTYPE html>
    <html xmlns:th="http://www.thymeleaf.org">
    <head>
        <title>로그인</title>
    </head>
    <body>
        <h1>로그인</h1>
        <form action="#" th:action="@{/login}" method="post">
            <label for="username">사용자 이름:</label>
            <input type="text" id="username" name="username" required><br>
            <label for="password">비밀번호:</label>
            <input type="password" id="password" name="password" required><br>
            <button type="submit">로그인</button>
        </form>
    </body>
    </html>
    

6. 결론

이번 강좌에서는 스프링 부트와 스프링 시큐리티를 사용하여 회원 가입 및 로그인/로그아웃 기능을 구현하는 방법에 대해 알아보았습니다. 기본적인 CRUD 기능과 RESTful API를 이해하고, 보안 기능을 추가하는 확장성 좋은 웹 애플리케이션을 만들 수 있는 기초를 쌓으셨길 바랍니다.

물론, 실전에서는 추가적인 보안 강화와 사용자 경험 향상을 위한 다양한 기능이 필요할 것입니다. 이러한 기능들을 추가하면서 더 심화된 내용을 탐구해 나가시길 바랍니다. 감사합니다!

Spring Boot Backend Development Course, Implementing Login and Logout with Spring Security, Adding Environment Variables for Testing

This course will provide a detailed explanation of how to develop a backend application using Spring Boot. The main topics include implementing user registration and login/logout features, using Spring Security, and setting up test environment variables.

1. What is Spring Boot?

Spring Boot is a tool that helps make the Spring framework easier to use, allowing for quick and easy application development. By using Spring Boot, applications can be easily run with minimal configuration, and it provides a variety of starter dependencies to enhance development convenience.

2. Introduction to Spring Security

Spring Security is a framework responsible for securing Spring-based applications. It provides authentication and authorization features to strengthen the application’s security. In this course, we will implement user registration, login, and logout through Spring Security.

3. Project Setup

To start the project, visit the Spring Boot initialization website (Spring Initializr), add the necessary dependencies, and create a new project. The following are the key dependencies to add:

  • Spring Web
  • Spring Security
  • Spring Data JPA
  • Spring Boot DevTools
  • H2 Database (used for testing)

4. Implementing User Registration Functionality

4.1. Creating the Entity Class

We will create a User entity class for the user registration functionality. This class will be used to store user information.

package com.example.demo.model;

import javax.persistence.*;

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    @Column(nullable = false, unique = true)
    private String username;
    
    @Column(nullable = false)
    private String password;
    
    public User() {}
    
    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }
    
    // getters and setters
}

4.2. Creating the Repository Interface

Create a JPA repository for the User entity.

package com.example.demo.repository;

import com.example.demo.model.User;
import org.springframework.data.jpa.repository.JpaRepository;

public interface UserRepository extends JpaRepository {
    User findByUsername(String username);
}

4.3. Writing the Service Class

We will create a service class to handle the business logic related to users.

package com.example.demo.service;

import com.example.demo.model.User;
import com.example.demo.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.stereotype.Service;

@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;
    
    @Autowired
    private PasswordEncoder passwordEncoder;
    
    public User registerUser(String username, String password) {
        User user = new User(username, passwordEncoder.encode(password));
        return userRepository.save(user);
    }
}

4.4. Implementing the Registration API

We will implement a RESTful API to handle user requests.

package com.example.demo.controller;

import com.example.demo.model.User;
import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api/auth")
public class AuthController {
    @Autowired
    private UserService userService;
    
    @PostMapping("/register")
    public User register(@RequestParam String username, @RequestParam String password) {
        return userService.registerUser(username, password);
    }
}

5. Implementing Login and Logout Functionality

5.1. Configuring Spring Security

We will configure Spring Security and add a filter to handle user authentication.

package com.example.demo.config;

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

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.inMemoryAuthentication()
            .withUser("user")
            .password(passwordEncoder().encode("password"))
            .roles("USER");
    }
    
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.csrf().disable()
            .authorizeRequests()
            .antMatchers("/api/auth/register").permitAll()
            .anyRequest().authenticated()
            .and()
            .httpBasic();
    }
    
    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }
}

5.2. Implementing the Login API

The login feature will be implemented through HTTP Basic Authentication. When a user sends authentication information (username and password) to the `/api/auth/login` endpoint, Spring Security will process it.

5.3. Implementing the Logout API

Logout will be implemented by invalidating the HTTP session. When a user sends a request to the `/api/auth/logout` endpoint, the session will be invalidated.

6. Adding Environment Variables for Testing

To manage sensitive information or configurations in the testing environment, we will create an `application-test.properties` file and set the environment variables.

# application-test.properties
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=password
spring.jpa.hibernate.ddl-auto=create-drop

7. Writing Test Cases

We will add test cases for the API using JUnit and Mockito. The test cases can be written for the UserService and AuthController.

7.1. Testing UserService

package com.example.demo.service;

import com.example.demo.model.User;
import com.example.demo.repository.UserRepository;
import org.junit.jupiter.api.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.security.crypto.password.PasswordEncoder;

import static org.mockito.Mockito.*;

@SpringBootTest
public class UserServiceTest {
    @InjectMocks
    private UserService userService;
    
    @Mock
    private UserRepository userRepository;
    
    @Mock
    private PasswordEncoder passwordEncoder;
    
    @BeforeEach
    public void setUp() {
        MockitoAnnotations.openMocks(this);
    }
    
    @Test
    public void testRegisterUser() {
        when(passwordEncoder.encode("password")).thenReturn("encodedPassword");
        when(userRepository.save(any(User.class))).thenReturn(new User("username", "encodedPassword"));
        
        User user = userService.registerUser("username", "password");
        
        assertEquals("username", user.getUsername());
        verify(userRepository).save(any(User.class));
    }
}

8. Conclusion

In this course, we learned how to apply Spring Security for user registration, login, and logout functionality in a backend application based on Spring Boot. We also explored how to add test environment variables and write test cases to improve the application’s quality. Based on this foundation, we encourage you to add more complex features and apply them in real-world projects.

9. References

Spring Boot Backend Development Course, Implementing Login and Logout with Spring Security, User Registration, Adding Dependencies

This course covers the basics of backend development using Spring Boot and explains how to implement login, logout, and user registration functionalities through Spring Security.

1. What is Spring Boot?

Spring Boot is an application framework based on the Spring Framework that helps developers set up and run Spring applications more easily. It minimizes the complex setup process and provides an embedded server, allowing developers to quickly build applications. Its main features include:

  • Auto Configuration: Developers can run their applications using default values without having to write configuration files.
  • Dependency Management: Required libraries can be easily added through Maven or Gradle.
  • Control over Dependencies: You can pin specific versions of libraries.

2. Creating a Project

There are various ways to create a new project using Spring Boot, but the easiest way to get started is to use Spring Initializr. Let’s follow the steps below to create a project.

  1. Access Spring Initializr
  2. Select Project: Maven Project
  3. Select Language: Java
  4. Select Spring Boot: Latest Version
  5. Input Group: com.example
  6. Input Artifact: demo
  7. Select Dependencies: Spring Web, Spring Security, Spring Data JPA, H2 Database
  8. Click Generate to download the ZIP file

3. Understanding Project Structure

When you open the generated project, you can see the following main directory and file structure.

    ├── src
    │   ├── main
    │   │   ├── java
    │   │   │   └── com
    │   │   │       └── example
    │   │   │           └── demo
    │   │   │               ├── DemoApplication.java
    │   │   │               └── configuration
    │   │   │                   └── SecurityConfig.java
    │   │   └── resources
    │   │       ├── application.properties
    │   │       └── static
    │   └── test
    ├── pom.xml
    

Here, the DemoApplication.java file is the main application file, and application.properties is the configuration file.

4. Adding Dependencies

The project we created includes the necessary libraries as Maven dependencies. Let’s open the pom.xml file to check the added dependencies.

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
    </dependencies>
    

5. Implementing Registration Functionality

To allow users to register, we need to save and manage user information. For this purpose, we will create a user entity using JPA and set up the connection to the database.

5.1 Creating the User Entity

First, let’s create an entity class called User. This class holds user information.

    package com.example.demo.model;

    import javax.persistence.*;

    @Entity
    public class User {
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Long id;
        
        private String username;
        private String password;
        private String email;

        // Getters and Setters
    }
    

5.2 Creating UserRepository

Now, we will create a UserRepository interface to save and retrieve user information from the database.

    package com.example.demo.repository;

    import com.example.demo.model.User;
    import org.springframework.data.jpa.repository.JpaRepository;

    public interface UserRepository extends JpaRepository {
        User findByUsername(String username);
    }
    

5.3 Writing the Registration Service

We will write a service class to handle the registration logic.

    package com.example.demo.service;

    import com.example.demo.model.User;
    import com.example.demo.repository.UserRepository;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;

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

        public User registerNewUser(User user) {
            return userRepository.save(user);
        }
    }
    

6. Configuring Spring Security

Now we will set up Spring Security to implement login and logout functionalities.

6.1 Creating SecurityConfig Class

We will create a class for security configuration.

    package com.example.demo.configuration;

    import com.example.demo.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
    import org.springframework.security.config.annotation.web.builders.HttpSecurity;
    import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
    import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;

    @Configuration
    @EnableWebSecurity
    public class SecurityConfig extends WebSecurityConfigurerAdapter {
        @Autowired
        private UserService userService;

        @Override
        protected void configure(AuthenticationManagerBuilder auth) throws Exception {
            auth.userDetailsService(userService);
        }

        @Override
        protected void configure(HttpSecurity http) throws Exception {
            http
                .authorizeRequests()
                    .antMatchers("/register", "/h2-console/**").permitAll()
                    .anyRequest().authenticated()
                .and()
                .formLogin()
                    .loginPage("/login")
                    .permitAll()
                .and()
                .logout()
                    .permitAll();
        }
    }
    

7. Implementing Registration and Login Controllers

We will write a controller to handle registration and login functionalities.

7.1 Creating AuthController Class

    package com.example.demo.controller;

    import com.example.demo.model.User;
    import com.example.demo.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.Model;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.PostMapping;

    @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(User user) {
            userService.registerNewUser(user);
            return "redirect:/login";
        }

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

8. Creating Login/Logout Pages

Now we will create the login and registration pages. Create login.html and register.html files under the src/main/resources/templates folder.

8.1 register.html

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>User Registration</title>
    </head>
    <body>
        <h1>User Registration</h1>
        <form action="/register" method="post">
            <label>Username: </label><input type="text" name="username"><br>
            <label>Password: </label><input type="password" name="password"><br>
            <label>Email: </label><input type="email" name="email"><br>
            <input type="submit" value="Register">
        </form>
    </body>
    </html>
    

8.2 login.html

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Login</title>
    </head>
    <body>
        <h1>Login</h1>
        <form action="/login" method="post">
            <label>Username: </label><input type="text" name="username"><br>
            <label>Password: </label><input type="password" name="password"><br>
            <input type="submit" value="Login">
        </form>
    </body>
    </html>
    

9. Running the Application

Now that all configurations are complete, enter the following command in the terminal to run the application.

    mvn spring-boot:run
    

Open your browser and navigate to http://localhost:8080/register to proceed with the registration. You can then access the application by logging in.

10. Conclusion and Next Steps

In this course, we learned how to build a backend application using Spring Boot and implement basic login and registration functionalities with Spring Security. Now you can build upon this basic structure to add various features such as API token-based authentication and OAuth2 integration.

Suggested Next Steps

  • Implement API REST
  • Add JWT (JSON Web Token) based authentication
  • Enhance authentication with OAuth2
  • Create a complete application with frontend integration

Make great use of what you learned in this course to create fantastic projects!

Author: [Your Name]

Published Date: [Publish Date]

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

This course guides you through the process of developing backend applications using Spring Boot and implementing login, logout, and signup features through Spring Security. You will understand the basic structure of Spring Boot and the concepts of Spring Security, and you will write actual code to implement these features.

Chapter 1: What is Spring Boot?

Spring Boot is a lightweight application development tool based on the Spring framework. Using Spring Boot, you can easily build production-level Spring applications. In this chapter, we will explore the features and advantages of Spring Boot and how to install it.

1.1 Features of Spring Boot

  • Auto Configuration: Spring Boot automatically configures settings according to the application’s requirements.
  • Standalone: Spring Boot applications can be run without separate server installations.
  • Dependency Management: You can easily manage library dependencies using Maven or Gradle.
  • Presets: It provides various Spring Boot starters for starting new applications.

Chapter 2: Setting Up a Spring Boot Project

We will use Spring Initializr to set up the project. This tool allows you to easily add dependencies and initial configurations.

2.1 Using Spring Initializr

  1. Access the Spring Initializr website.
  2. Enter the project metadata (Group, Artifact, Name, etc.).
  3. Select the required dependencies (Spring Web, Spring Security, etc.).
  4. Unzip the downloaded ZIP file and open it in your IDE.

Chapter 3: Understanding the Basics of Spring Security

Spring Security is a framework that provides powerful and comprehensive authentication and authorization capabilities. In this chapter, we will understand the basic concepts of Spring Security and learn how to implement login and logout.

3.1 Authentication and Authorization

Authentication is the process of verifying a user’s identity, while Authorization is the process of verifying a user’s permissions to perform specific actions.

Chapter 4: Implementing Signup Features

Now you are ready to implement a simple signup feature. We will set up the necessary model, controller, and service layers.

4.1 Creating the User Model

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String username;
    private String password;

    // Getters and Setters
}

4.2 Implementing the Signup API

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api/auth")
public class AuthController {

    @Autowired
    private UserService userService;

    @PostMapping("/register")
    public ResponseEntity register(@RequestBody User user) {
        return userService.register(user);
    }
}

Chapter 5: Implementing Login and Logout Features

With the signup feature implemented, we will now set up the login and logout features. We will implement the authentication process using Spring Security.

5.1 Configuring Spring Security

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

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.inMemoryAuthentication()
            .withUser("user").password(passwordEncoder().encode("password")).roles("USER");
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.csrf().disable()
            .authorizeRequests()
            .antMatchers("/api/auth/register").permitAll()
            .anyRequest().authenticated()
            .and()
            .httpBasic();
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }
}

5.2 Implementing the Login API

The login API can be handled using the basic functionalities of Spring Security. You can create a custom login page or utilize the default authentication of Spring Security.

Chapter 6: Writing Controllers

Finally, we will write a RESTful API controller to manage communication with the client. We will define and implement requirements for each endpoint.

6.1 Implementing the User API

import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api/users")
public class UserController {

    @GetMapping("/{id}")
    public ResponseEntity getUser(@PathVariable Long id) {
        // logic to get user by id
    }

    @PutMapping("/{id}")
    public ResponseEntity updateUser(@PathVariable Long id, @RequestBody User user) {
        // logic to update user
    }
}

Conclusion

Through this course, you have learned the basics of backend development using Spring Boot and the concepts of authentication and authorization through Spring Security. I hope you continue to develop and expand upon the additional features you need.