Kaptcha image verification code integration

technological process ： Generate pictures ----> Put the verification code data into session in ----> Login interface for comparison .

Here to session Explain ： When the server is getSession(true) Created on Session At the same time , The server will be Session Generate unique Session id, And this Session id It will be used in subsequent requests to retrieve the created Session; stay Session After being created , You can call Session Related methods Session Added to , And that content will only be stored on the server , Only Session id; When the client sends the request again , Will take this. Session id close , After the server receives the request, it will base on Session id Find the appropriate Session, So that it can be used again . So it's safe .

1, Import dependence

<!-- Verification Code -->
        <dependency>
            <groupId>com.github.penggle</groupId>
            <artifactId>kaptcha</artifactId>
        </dependency>

2, You can put bean Inject Spring in , When you want to use it Autowired Use .

/**
     *  Verification code generation related 
     */
    @Bean
    public DefaultKaptcha kaptcha() {
        Properties properties = new Properties();
        properties.put("kaptcha.border", "no");
        properties.put("kaptcha.border.color", "105,179,90");
        properties.put("kaptcha.textproducer.font.color", "blue");
        properties.put("kaptcha.image.width", "125");
        properties.put("kaptcha.image.height", "45");
        properties.put("kaptcha.textproducer.font.size", "45");
        properties.put("kaptcha.session.key", "code");
        properties.put("kaptcha.textproducer.char.length", "4");
        properties.put("kaptcha.textproducer.font.names", " Song style , Regular script , Microsoft YaHei ");
        Config config = new Config(properties);
        DefaultKaptcha defaultKaptcha = new DefaultKaptcha();
        defaultKaptcha.setConfig(config);
        return defaultKaptcha;
    }

3, Provide an interface for generating pictures , And save the verification code into session in , Then compare the login interface .

    @Autowired
    private Producer producer;

    /**
     *  Generate verification code 
     */
    @RequestMapping("/verificationCode")
    public void index(HttpServletRequest request, HttpServletResponse response) {
        HttpSession session = request.getSession();

        response.setDateHeader("Expires", 0);

        // Set standard HTTP/1.1 no-cache headers.
        response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");

        // Set IE extended HTTP/1.1 no-cache headers (use addHeader).
        response.addHeader("Cache-Control", "post-check=0, pre-check=0");

        // Set standard HTTP/1.0 no-cache header.
        response.setHeader("Pragma", "no-cache");

        // return a jpeg
        response.setContentType("image/jpeg");

        // create the text for the image
        String capText = producer.createText();

        // store the text in the session
        session.setAttribute(Constants.KAPTCHA_SESSION_KEY, capText);

        // create the image with the text
        BufferedImage bi = producer.createImage(capText);
        ServletOutputStream out = null;
        try {
            out = response.getOutputStream();
        } catch (IOException e) {
            e.printStackTrace();
        }

        // write the data out
        try {
            ImageIO.write(bi, "jpg", out);
        } catch (IOException e) {
            e.printStackTrace();
        }
        try {
            try {
                out.flush();
            } catch (IOException e) {
                e.printStackTrace();
            }
        } finally {
            try {
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

4, Just compare .

This article has references to other frameworks , any similarity , It was an accident .