spring security redis

### Spring Security 集成 Redis 实现会话管理与认证授权

#### 1. 添加依赖项
为了使项目能够使用 Spring Security 和 Redis，需要在 `pom.xml` 文件中添加必要的 Maven 依赖。

<dependencies>
    <!-- Spring Boot Starter Security -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-security</artifactId>
    </dependency>

    <!-- Spring Data Redis -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-redis</artifactId>
    </dependency>

    <!-- Lettuce 连接池 (默认配置) -->
    <dependency>
        <groupId>io.lettuce</groupId>
        <artifactId>lettuce-core</artifactId>
    </dependency>
    
    <!-- JSON Web Token 支持 -->
    <dependency>
        <groupId>io.jsonwebtoken</groupId>
        <artifactId>jjwt-api</artifactId>
        <version>0.11.2</version>
    </dependency>
    <dependency>
        <groupId>io.jsonwebtoken</groupId>
        <artifactId>jjwt-impl</artifactId>
        <version>0.11.2</version>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>io.jsonwebtoken</groupId>
        <artifactId>jjwt-jackson</artifactId>
        <version>0.11.2</version>
        <scope>runtime</scope>
    </dependency>
</dependencies>

#### 2. 配置 Redis 连接工厂
通过自定义 Bean 来覆盖默认的连接设置，确保应用程序能正确访问到 Redis 数据库实例。

@Configuration
public class RedisConfig {

    @Bean
    public LettuceConnectionFactory redisConnectionFactory() {
        return new LettuceConnectionFactory();
    }
}

#### 3. 设置 Session 存储位置为 Redis
修改 application.properties 或者 yml 文件来指定 session 的存储方式：

server.servlet.session.timeout=86400 # 单位秒,一天有效期
spring.redis.host=localhost          # Redis服务器地址
spring.redis.port=6379               # Redis端口号
spring.session.store-type=redis      # 使用Redis作为session仓库

#### 4. 自定义 UserDetailsService 接口实现类
创建一个服务组件用于加载用户特定数据，并返回 UserDetails 对象给框架处理验证逻辑。

@Service
public class CustomUserDetailService implements UserDetailsService {

    private final UserRepository userRepository;

    @Autowired
    public CustomUserDetailService(UserRepository userRepository){
        this.userRepository = userRepository;
    }

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        Optional<UserEntity> userOpt = userRepository.findByUsername(username);
        
        if (!userOpt.isPresent()) throw new UsernameNotFoundException("Invalid username or password.");
        
        UserEntity user = userOpt.get();

        Set<GrantedAuthority> authorities = Collections.singleton(new SimpleGrantedAuthority(user.getRole().name()));

        return new org.springframework.security.core.userdetails.User(
            user.getUsername(), 
            user.getPassword(),
            authorities
        );
    }
}

#### 5. 创建 JWT 工具类
编写工具方法来进行 token 的生成和解析操作。

@Component
public class JwtUtil {

    private static final String SECRET_KEY = "secret";

    public String generateToken(UserDetails userDetails) {
        Map<String, Object> claims = new HashMap<>();
        return createToken(claims, userDetails.getUsername());
    }

    private String createToken(Map<String, Object> claims, String subject) {
        return Jwts.builder()
                .setClaims(claims)
                .setSubject(subject)
                .setIssuedAt(new Date(System.currentTimeMillis()))
                .setExpiration(new Date(System.currentTimeMillis() + 1000 * 60 * 60 * 10)) // 有效时间十分钟
                .signWith(SignatureAlgorithm.HS256, SECRET_KEY.getBytes())
                .compact();
    }

    public Boolean validateToken(String token, UserDetails userDetails) {
        final String username = extractUsername(token);
        return (
              username.equals(userDetails.getUsername())
            && !isTokenExpired(token));
    }

    private Boolean isTokenExpired(String token) {
        return extractExpiration(token).before(new Date());
    }

    public String extractUsername(String token) {
        return extractClaim(token, Claims::getSubject);
    }

    public Date extractExpiration(String token) {
        return extractClaim(token, Claims::getExpiration);
    }

    public <T> T extractClaim(String token, Function<Claims, T> claimsResolver) {
        final Claims claims = extractAllClaims(token);
        return claimsResolver.apply(claims);
    }

    private Claims extractAllClaims(String token) {
        try{
            return Jwts.parserBuilder()
                    .setSigningKey(SECRET_KEY.getBytes())
                    .build()
                    .parseClaimsJws(token)
                    .getBody();
        }catch(Exception e){
            System.out.println(e.getMessage());
            return null;
        }
    }
}

#### 6. 构建过滤器链并注册至安全上下文中
最后一步是在全局范围内应用这些更改，即向 HTTP 请求管道注入新的身份验证机制。

@EnableWebSecurity
public class SecurityConfigurer extends WebSecurityConfigurerAdapter {

    private final JwtRequestFilter jwtRequestFilter; 

    @Autowired
    public SecurityConfigurer(JwtRequestFilter jwtRequestFilter) {this.jwtRequestFilter = jwtRequestFilter;}

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.csrf().disable()
           .authorizeRequests()
             .antMatchers("/authenticate").permitAll()
             .anyRequest().authenticated()
           .and()
           .sessionManagement()
             .sessionCreationPolicy(SessionCreationPolicy.STATELESS);

        http.addFilterBefore(jwtRequestFilter, UsernamePasswordAuthenticationFilter.class);
    }

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

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

    @Bean
    public CustomUserDetailService customUserDetailService(){
        return new CustomUserDetailService(null); // 此处应传入实际的服务层对象
    }

    @Bean
    public JwtRequestFilter authenticationJwtTokenFilter(){
        return new Jwt