Spring Boot 4 Complete Guide · Aula

Fundamentos do Spring Security

Configure o Spring Security, entenda sua arquitetura e implemente a autenticação básica em memória.

Aula 1 de 412 etapas

Fundamentos do Spring Security é uma aula grátis de Spring Boot 4 Complete Guide no CoddyKit. Esta é a aula 1 de 4. Você pode ler a aula completa abaixo gratuitamente — depois pratica ao vivo no navegador com um editor de código integrado e um tutor de IA 24/7. Faz parte do caminho de aprendizado de Spring Boot 4 Complete Guide, e seu progresso é sincronizado entre a web e o app CoddyKit. O curso de Spring Boot 4 Complete Guide inclui 4 aulas no total.

Partes desta aula ainda não foram traduzidas e aparecem em inglês.

Welcome to Spring Security!

Securing web applications is crucial in today's digital world. Spring Security is a powerful and highly customizable authentication and access-control framework for Spring applications.

It provides robust security features, allowing you to protect your application from common vulnerabilities and control who can access what.

Why Spring Security?

Imagine building an online store. You need to:

Authenticate users: Verify a user's identity (login).
Authorize actions: Determine what a user can do (e.g., only admins can delete products).
Protect against threats: CSRF, XSS, session fixation.

Spring Security handles all these complex tasks, letting you focus on your application's core logic.

Adding the Security Dependency

To get started, you just need to add the spring-boot-starter-security dependency to your project. This starter brings in all necessary Spring Security modules.

For Maven, add this to your pom.xml:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>

Default Security in Action

Once the dependency is added, Spring Boot automatically configures basic security. Try running this simple application:

package com.coddykit;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class SecurityApp {

    public static void main(String[] args) {
        SpringApplication.run(SecurityApp.class, args);
    }

    @GetMapping("/hello")
    public String hello() {
        return "Hello, Secured World!";
    }
}

Default Login & Password

When you run the previous code with the Spring Security dependency, you'll notice something:

Accessing /hello redirects you to a login page.
Spring Security generates a random password, printed in the console at startup.

The username is typically user, and the password is the generated one. This is basic, out-of-the-box security!

AuthN vs. AuthZ

Let's clarify two fundamental concepts:

Authentication (AuthN): Verifying who you are. This is typically done with credentials like username/password.
Authorization (AuthZ): Determining what you are allowed to do once authenticated. For example, a user might be authenticated, but only an 'admin' role can delete data.

Spring Security handles both!

The Security Filter Chain

At its core, Spring Security works by intercepting HTTP requests. It uses a series of filters, called the Security Filter Chain, to apply security logic.

When a request comes in, these filters perform tasks like authentication, authorization, session management, and more, before the request even reaches your controller.

Basic In-Memory Authentication

For simple applications or testing, you can define users directly in your application's memory. This is called in-memory authentication.

You'll configure a UserDetailsService bean that provides user details. Let's see how to define a custom user with a specific role.

Configuring In-Memory Users

Here's how to define a user 'john' with password 'pass' and role 'USER'. Remember to encode passwords!

package com.coddykit;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
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.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.security.provisioning.InMemoryUserDetailsManager;
import org.springframework.security.web.SecurityFilterChain;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
@EnableWebSecurity
public class SecurityConfigApp {

    public static void main(String[] args) {
        SpringApplication.run(SecurityConfigApp.class, args);
    }

    @GetMapping("/public")
    public String publicAccess() {
        return "This is a public page!";
    }

    @GetMapping("/user")
    public String userAccess() {
        return "Welcome, authenticated user!";
    }

    @Configuration
    static class WebSecurityConfig {

        @Bean
        public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
            http
                .authorizeHttpRequests(authorize -> authorize
                    .requestMatchers("/public").permitAll()
                    .requestMatchers("/user").hasRole("USER")
                    .anyRequest().authenticated()
                )
                .formLogin(login -> login
                    .permitAll()
                );
            return http.build();
        }

        @Bean
        public UserDetailsService userDetailsService(PasswordEncoder passwordEncoder) {
            UserDetails user = User.builder()
                .username("john")
                .password(passwordEncoder.encode("pass"))
                .roles("USER")
                .build();
            return new InMemoryUserDetailsManager(user);
        }

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

Testing In-Memory Users

Run the previous application. Now try accessing:

http://localhost:8080/public: Should be accessible without login.
http://localhost:8080/user: Should redirect to login. Use username 'john' and password 'pass'.
http://localhost:8080/admin: Should redirect to login, then show 403 Forbidden even after logging in as 'john', because 'john' doesn't have the 'ADMIN' role.

Quick Check: Spring Security

You've learned about the basics of Spring Security and in-memory authentication. Let's test your understanding.

Responda na aula interativa

Lesson Summary

Great job! In this lesson, you've taken your first steps with Spring Security:

Understood its purpose and core concepts (AuthN, AuthZ).
Added the necessary dependency and observed default behavior.
Learned about the Security Filter Chain.
Implemented basic in-memory authentication with custom users and role-based URL protection.

Next, we'll explore how to handle authentication and authorization using databases and more advanced techniques!

Grátis para começar

Aprenda Java com um tutor de IA — grátis

Escreva e execute código real no seu navegador, obtenha ajuda instantânea de um tutor de IA 24/7 e continue de onde parou na web ou no app.

Cursos: 21
Aulas: 84

Começar a aprender grátis Ver o curso completo

Perguntas Frequentes

A aula “Fundamentos do Spring Security” é grátis?

Sim — o texto completo de “Fundamentos do Spring Security” é grátis para ler aqui na web. Para praticá-la interativamente (um editor de código integrado e um tutor de IA 24/7) e desbloquear o restante do curso de Spring Boot 4 Complete Guide, atualize para CoddyKit PRO. O curso de Spring Boot 4 Complete Guide inclui 4 aulas no total.

O que vou aprender em “Fundamentos do Spring Security”?

Configure o Spring Security, entenda sua arquitetura e implemente a autenticação básica em memória. Você pratica Spring Boot 4 Complete Guide com código prático que executa diretamente no navegador, e um tutor de IA 24/7 responde suas dúvidas enquanto trabalha na aula.

Preciso ter experiência prévia para começar Spring Boot 4 Complete Guide?

Nenhuma experiência prévia é necessária. Spring Boot 4 Complete Guide no CoddyKit é estruturado para alunos iniciantes até avançados, então você pode começar aqui ou desde o início e aprender no seu ritmo. Esta é a aula 1 de 4.

Quanto tempo leva a aula “Fundamentos do Spring Security”?

A maioria das aulas CoddyKit leva cerca de 5–10 minutos. Cada uma é compacta e interativa, então você faz progresso constante e retoma exatamente de onde parou entre web e app.

Posso escrever e executar código nesta aula de Spring Boot 4 Complete Guide?

Sim. Cada aula de Spring Boot 4 Complete Guide inclui um editor de código integrado, então você escreve e executa código real direto no navegador e recebe feedback de IA instantaneamente — nenhuma configuração local necessária.

Todas as aulas deste curso

← Voltar para Spring Boot 4 Complete Guide