前言

在前面的几篇文章中：
spring boot security快速使用示例
spring boot security之前后端分离配置
spring boot security自定义认证
spring boot security验证码登录示例
基本对常用的基于cookie和session的认证使用场景都已覆盖。但是session属于有状态认证，本文给出一个无状态的认证：jwt认证示例。

代码示例

下面会提供完整的示例代码：

依赖

使用的spring boot 2.6.11版本，jdk8。

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

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

		<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.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<version>1.18.20</version>
			<scope>provided</scope>
		</dependency>

		<dependency>
			<groupId>com.github.penggle</groupId>
			<artifactId>kaptcha</artifactId>
			<version>2.3.2</version>
		</dependency>

		<dependency>
			<groupId>io.jsonwebtoken</groupId>
			<artifactId>jjwt</artifactId>
			<version>0.9.1</version>
		</dependency>

定义mapper

定义一个查询用户信息的接口：

@Component
public class UserMapper {

   public User select(String username) {
        return new User(username, "pass");
    }
}

定义用户信息的实体bean

@Data
public class User {

    private String username;

    private String password;

    private String captcha;

    public User() {
    }

    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }

    public User(String username, String password, String captcha) {
        this.username = username;
        this.password = password;
        this.captcha = captcha;
    }
}

security相关的类

1. 实现spring security内置的UserDetailsService接口，根据用户名返回用户信息：

@Slf4j
@Component
public class UserDetailsServiceImpl implements UserDetailsService {

    public static final UserDetails INVALID_USER =
            new org.springframework.security.core.userdetails.User("invalid_user", "invalid_password", Collections.emptyList());

    private final UserMapper userMapper;

    public UserDetailsServiceImpl(UserMapper userMapper) {
        this.userMapper = userMapper;
    }

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        // 根据用户名从数据库查询用户信息
        User user = userMapper.select(username);
        if (user == null) {
            /**
             * 如果没查询到这个用户，考虑两种选择：
             * 1. 返回一个标记无效用户的常量对象
             * 2. 返回一个不可能认证通过的用户
             */
            return INVALID_USER;
//            return new User(username, System.currentTimeMillis() + UUID.randomUUID().toString(), Collections.emptyList());
        }
        /**
         * 这里返回的用户密码是否为库里保存的密码，是明文/密文，取决于认证时密码比对部分的实现，每个人的场景不一样，
         * 因为使用的是不加密的PasswordEncoder，所以可以返回明文
         */
        return new org.springframework.security.core.userdetails.User(username, user.getPassword(), Collections.emptyList());
    }
}

2. 定义jwt工具类

public class JwtUtil {

    public static final String SECRET = TextCodec.BASE64.encode("secret");

    public static final long EXPIRE_SECONDS = 3600L;

    /**
     * 从token中解析出用户名
     */
    public static String getUsernameFromToken(String token) {
        return getClaimFromToken(token, Claims::getSubject);
    }

    /**
     * 从token中获取过期时间
     */
    public static Date getExpirationDateFromToken(String token) {
        return getClaimFromToken(token, Claims::getExpiration);
    }

    /**
     * 解析出token声明.
     */
    public static <T> T getClaimFromToken(String token, Function<Claims, T> claimsResolver) {
        final Claims claims = Jwts.parser().setSigningKey(SECRET).parseClaimsJws(token).getBody();
        return claimsResolver.apply(claims);
    }

    /**
     * token是否过期
     */
    public static Boolean isTokenExpired(String token) {
        final Date expiration = getExpirationDateFromToken(token);
        return expiration.before(new Date());
    }

    /**
     * 生成token
     */
    public static String generateToken(UserDetails userDetails) {
        Map<String, Object> claims = new HashMap<>();
        return doGenerateToken(claims, userDetails.getUsername());
    }

    /**
     * token是否合法.
     */
    public static Boolean isValidateToken(String token, UserDetails userDetails) {
        final String username = getUsernameFromToken(token);
        return (username.equals(userDetails.getUsername()) && !isTokenExpired(token));
    }

    private static String doGenerateToken(Map<String, Object> claims, String subject) {
        return Jwts.builder().setClaims(claims).setSubject(subject).setIssuedAt(new Date(System.currentTimeMillis()))
                .setExpiration(new Date(System.currentTimeMillis() + EXPIRE_SECONDS * 1000))
                .signWith(SignatureAlgorithm.HS512, SECRET).compact();
    }

}

3. 定义jwt认证的过滤器

@Slf4j
@Component
public class JwtRequestFilter extends OncePerRequestFilter {


    private final UserDetailsService userDetailsService;


    public JwtRequestFilter(UserDetailsService userDetailsService) {
        this.userDetailsService = userDetailsService;
    }

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
            throws ServletException, IOException {

        final String requestTokenHeader = request.getHeader(HttpHeaders.AUTHORIZATION);

        String username = null;
        String jwtToken = null;
        if (requestTokenHeader != null && requestTokenHeader.startsWith("Bearer ")) {
            jwtToken = requestTokenHeader.substring(7);
            try {
                username = JwtUtil.getUsernameFromToken(jwtToken);
            } catch (Exception e) {
                log.error("获取token失败: {}, {}", jwtToken, e.getMessage());
            }
        }

        if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
            // 根据用户名加载用户信息
            UserDetails userDetails = this.userDetailsService.loadUserByUsername(username);
            // 判断token是否有效
            if (JwtUtil.isValidateToken(jwtToken, userDetails)) {
                UsernamePasswordAuthenticationToken usernamePasswordAuthenticationToken = new UsernamePasswordAuthenticationToken(
                        userDetails, null, userDetails.getAuthorities());
                usernamePasswordAuthenticationToken
                        .setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
                SecurityContextHolder.getContext().setAuthentication(usernamePasswordAuthenticationToken);
            }
        }
        chain.doFilter(request, response);
    }

}

4. 注册相关bean到spring容器

@Configuration
public class WebConfiguration {

    @Bean
    public PasswordEncoder passwordEncoder() {
        // 示例，不对密码进行加密处理
        return NoOpPasswordEncoder.getInstance();
    }


    @Bean
    public AuthenticationManager authenticationManager(UserDetailsService userDetailsService, PasswordEncoder passwordEncoder) {
        DaoAuthenticationProvider provider = new DaoAuthenticationProvider();
        // 设置加载用户信息的类
        provider.setUserDetailsService(userDetailsService);
        // 比较用户密码的时候，密码加密方式
        provider.setPasswordEncoder(passwordEncoder);
        return new ProviderManager(Arrays.asList(provider));
    }
    
    @Bean
    public Producer defaultKaptcha() {
        Properties properties = new Properties();
        // 还有一些其它属性，可以进行源码自己看相关配置，比较清楚了，根据变量名也能猜出来什么意思了
        properties.setProperty(Constants.KAPTCHA_IMAGE_WIDTH, "150");
        properties.setProperty(Constants.KAPTCHA_IMAGE_HEIGHT, "50");
        properties.setProperty(Constants.KAPTCHA_TEXTPRODUCER_CHAR_STRING, "0123456789abcdefghigklmnopqrstuvwxyz");
        properties.setProperty(Constants.KAPTCHA_TEXTPRODUCER_CHAR_LENGTH, "4");
        Config config = new Config(properties);
        DefaultKaptcha defaultKaptcha = new DefaultKaptcha();
        defaultKaptcha.setConfig(config);
        return defaultKaptcha;
    }

}

5. 自定义 WebSecurityConfigurer

@Component
public class WebSecurityConfigurer extends WebSecurityConfigurerAdapter {

    private final JwtRequestFilter jwtRequestFilter;

    public WebSecurityConfigurer(JwtRequestFilter jwtRequestFilter) {
        this.jwtRequestFilter = jwtRequestFilter;
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        // 在这里自定义配置
        http.authorizeRequests()
                // 登录相关接口都允许访问
                .antMatchers("/login/**").permitAll()
                .anyRequest()
                .authenticated()
                .and()
                .exceptionHandling()
                // 认证失败返回401状态码，前端页面可以根据401状态码跳转到登录页面
                .authenticationEntryPoint((request, response, authException) ->
                        response.sendError(HttpStatus.UNAUTHORIZED.value(), HttpStatus.UNAUTHORIZED.getReasonPhrase()))
                .and().cors()
                // csrf是否决定禁用，请自行考量
                .and().csrf().disable()
                // 采用http 的基本认证.
                .httpBasic()
                // 设置session是无关的
                .and().sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS)
                .and().addFilterBefore(jwtRequestFilter, UsernamePasswordAuthenticationFilter.class);

    }
}

提供登录接口

@RequestMapping("/login")
@RestController
public class LoginController {

    private final AuthenticationManager authenticationManager;

    private final Producer producer;

    public LoginController(AuthenticationManager authenticationManager, Producer producer) {
        this.authenticationManager = authenticationManager;
        this.producer = producer;
    }

    @PostMapping()
    public Object login(@RequestBody User user, HttpSession session) {
        Object captcha = session.getAttribute(Constants.KAPTCHA_SESSION_KEY);
        if (captcha == null || !captcha.toString().equalsIgnoreCase(user.getCaptcha())) {
            return "captcha is not correct.";
        }
        try {
            // 使用定义的AuthenticationManager进行认证处理
            Authentication authenticate = authenticationManager.authenticate(new UsernamePasswordAuthenticationToken(user.getUsername(), user.getPassword()));
            // 认证通过，设置到当前上下文，如果当前认证过程后续还有处理的逻辑需要的话。这个示例是没有必要了
            SecurityContextHolder.getContext().setAuthentication(authenticate);
            String token = JwtUtil.generateToken((UserDetails) authenticate.getPrincipal());
            return token;
        } catch (Exception e) {
            return "login failed";
        }
    }

    /**
     * 获取验证码，需要的话，可以提供一个验证码获取的接口，在上面的login里把验证码传进来进行比对
     */
    @GetMapping("/captcha")
    public void captcha(HttpServletResponse response, HttpSession session) throws IOException {
        response.setContentType("image/jpeg");
        String text = producer.createText();
        session.setAttribute(Constants.KAPTCHA_SESSION_KEY, text);
        BufferedImage image = producer.createImage(text);
        try (ServletOutputStream out = response.getOutputStream()) {
            ImageIO.write(image, "jpg", out);
        }
    }
}

测试

提供一个用于测试的接口

@RequestMapping("/hello")
@RestController
public class HelloController {

    @GetMapping("/world")
    public Object helloWorld() {
        return "hello, world";
    }
}

验证

1. 获取验证码
   
2. 登录
   
3. 使用登录的token访问接口
   
4. 如果没有token或不正确是访问受限的