SpringBoot+kaptcha实现图片验证码功能详解

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.1</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>SpringBoot-VerifyCode</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>SpringBoot-VerifyCode</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

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

		<!-- 验证码生成包 -->
        <dependency>
            <groupId>com.github.penggle</groupId>
            <artifactId>kaptcha</artifactId>
            <version>2.3.2</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

package com.example.springbootverifycode;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringBootVerifyCodeApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringBootVerifyCodeApplication.class, args);
    }

}

package com.example.springbootverifycode.config;

import com.google.code.kaptcha.Producer;
import com.google.code.kaptcha.impl.DefaultKaptcha;
import com.google.code.kaptcha.util.Config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.Properties;

@Configuration
public class VerifyCodeConfig {

    @Bean
    Producer producer() {
        Properties properties = new Properties();
        //设置图片边框
        properties.setProperty("kaptcha.border", "yes");
        //设置图片边框为蓝色
        properties.setProperty("kaptcha.border.color", "blue");
        //背景颜色渐变开始
        properties.put("kaptcha.background.clear.from", "127,255,212");
        //背景颜色渐变结束
        properties.put("kaptcha.background.clear.to", "240,255,255");
        // 字体颜色
        properties.put("kaptcha.textproducer.font.color", "black");
        // 文字间隔
        properties.put("kaptcha.textproducer.char.space", "10");
        //如果需要去掉干扰线
		properties.put("kaptcha.noise.impl", "com.google.code.kaptcha.impl.NoNoise");
        // 字体
        properties.put("kaptcha.textproducer.font.names", "Arial,Courier,cmr10,宋体,楷体,微软雅黑");
        // 图片宽度
        properties.setProperty("kaptcha.image.width", "200");
        // 图片高度
        properties.setProperty("kaptcha.image.height", "50");
        // 从哪些字符中产生
        properties.setProperty("kaptcha.textproducer.char.string", "0123456789abcdefghijklmnopqrsduvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ");
        // 字符个数
        properties.setProperty("kaptcha.textproducer.char.length", "6");
        DefaultKaptcha defaultKaptcha = new DefaultKaptcha();
        defaultKaptcha.setConfig(new Config(properties));
        return defaultKaptcha;
    }
}

package com.example.springbootverifycode.controller;

import com.google.code.kaptcha.Producer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.awt.image.BufferedImage;
import java.io.IOException;

@RestController
public class KaptchaController {

    @Autowired
    private Producer producer;

    @GetMapping("/getVerifyCode")
    public void getVerifyCode(HttpServletResponse response, HttpSession session) throws IOException {
        response.setContentType("image/jpeg");
        String text = producer.createText();
        session.setAttribute("vf", text);
        BufferedImage image = producer.createImage(text);
        try (ServletOutputStream sos = response.getOutputStream()) {
            ImageIO.write(image, "jpg", sos);
        }
    }
}

 // 文字个数
 properties.put("kaptcha.textproducer.char.space", "7");

 @GetMapping("/getCal")
    public void getCal(HttpServletResponse response, HttpSession session) throws IOException {
        response.setContentType("image/jpeg");
        //生成文字验证码
        String text = producer.createText();
        System.out.println("当前生成的字符串为:" + text);
        //个位数字相加
        String s1 = text.substring(0, 2);
        String s2 = text.substring(2, 4);
        int count = Integer.valueOf(s1).intValue() + Integer.valueOf(s2).intValue();
        System.out.println("计算结果为:" + count);
        //生成图片验证码
        BufferedImage image = producer.createImage(s1 + "+" + s2 + "=?");
        try (ServletOutputStream sos = response.getOutputStream()) {
            ImageIO.write(image, "jpg", sos);
        }
    }