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.