How to integrate Kaptcha verification codes in SpringBoot

Updated: January 6, 2025 10:49:28 Author: Runtu, a young man who loves JAVA

This article introduces how to use Kaptcha to generate verification codes in Java development, including configuration dependencies in the system, adding configurations in the common configuration class, adding methods to generate verification codes in the controller, and how to reference the front-end page. At the same time, it also adds more configuration properties and default values of Kaptcha.

SpringBoot Integrated Kaptcha Verification Code

Introduction

In development, the verification code function is a common and important feature. Kaptcha is a plug-in for generating verification codes provided by the famous Google company, which supports highly configurable;

This chapter will show how to implement verification code functionality through a simple example

Implementation steps

1. In the configuration file

Add the following configuration:

Since access to Google's network is restricted in China, it is recommended to use the following dependency download

<dependency>
    <groupId></groupId>
    <artifactId>kaptcha</artifactId>
    <version>2.3.2</version>
</dependency>

2. Add the following code to the system public configuration class

Of course, Kaptcha configuration can also be added to the configuration file

@Configuration
public class AppConfigure implements WebMvcConfigurer {
    /**
      * Verification code configuration
      */
    @Bean
    public DefaultKaptcha kaptcha() {
        DefaultKaptcha kaptcha = new DefaultKaptcha();
        Properties properties = new Properties();
        ("", "yes");
        ("", "100");
        ("", "33");
        ("", "code");
        ("", "105,179,90");
        ("", "30");
        ("", "4");
        ("", "blue");
        ("", "Song style,Kaiyi,Microsoft Yahei");
        (new Config(properties));
        return kaptcha;
    }
}

3. Add a method to provide verification code generation in

@Controller
@RequestMapping("/kaptcha")
@Slf4j
public class KaptchaController {
    @Resource
    private DefaultKaptcha kaptcha;
    
    /**
      * Application verification code
      */
    @GetMapping("/kaptcha")
    public void getKaptcha(HttpServletRequest request, HttpServletResponse response) {
            ("Expires", 0);
            ("Cache-Control", "no-store, no-cache, must-revalidate");
            ("Cache-Control", "post-check=0, pre-check=0");
            ("Pragma", "no-cache");
            ("image/jpeg");

            HttpSession session = ();
            ServletOutputStream outputStream = null;
            try {
                //Generate verification code                String kaptchaText = ();
                // Save the verification code for 5 minutes                (session, (), kaptchaText, 
                    Properties.EXPIRETIME_KAPTCHA.value());
                ("captcha code: " + kaptchaText);
                //Export to the client                BufferedImage bufferedImage = (kaptchaText);
                outputStream = ();
                (bufferedImage, "jpg", outputStream);
                ();
            } catch (IOException e) {
                throw new BusinessException(ErrorCode.CLOSE_IO_EXCEPTION);
            } finally {
                (outputStream);
            }
        }
        ......
}

4. Use the img tag to directly reference the front-end page

&lt;img src="/kaptcha/kaptcha"  title="Click to refresh"&gt;

Additional: Kaptcha more configurations

Attributes (constant)	describe	default value
	Image border, legal value: yes, no	yes
	Border color, legal value: r,g,b (and optional alpha) or white,black,blue.	black
	Border thickness, legal value: >0	1
	Picture wide	200
	High picture	50
	Image implementation class
	Text implementation class
	Text collection, verification code value is obtained from this collection	abcde2345678gfynmnpwx
	Verification code length	5
	Font	Arial, Courier
	Font size	40px
	Font color, legal values: r,g,b or white,black,blue.	black
	Text interval	2
	Interference implementation class
	Interference color, legal value: r,g,b or white,black,blue.	black
	Picture style: water pattern, fish eyes, shadow
	Background implementation class
	Background color gradient, start color	light grey
	Background color gradient, end color	white
	Text Renderer
	session key	KAPTCHA_SESSION_KEY
	session date	KAPTCHA_SESSION_DATE

Summarize

The above is personal experience. I hope you can give you a reference and I hope you can support me more.

SpringBoot
integrated
Kaptcha
Verification code

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