springboot security验证码的登录实例

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

@Configuration
public class CaptchaConfiguration {


    @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;
    }
}

@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);
            return "login success";
        } 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);
        }
    }
}