package cn.god23bin.demo.util;
import java.util.Random;
public class MyCaptchaUtil {
	/**
     * 生成 n 位驗(yàn)證碼
     * @param n 位數(shù)
     * @return n 位驗(yàn)證碼
     **/
    public static String generateCode(int n) {
        String chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        StringBuilder sb = new StringBuilder();
        Random random = new Random();
        for (int i = 0; i < n; i++) {
            int index = random.nextInt(chars.length());
            sb.append(chars.charAt(index));
        }
        return sb.toString();
    }
}

package cn.god23bin.demo.util;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.HashMap;
import java.util.Map;
public class MyCaptchaUtil {
	/**
     * 生成 n 位的圖片驗(yàn)證碼
     * @param n 位數(shù)
     * @return 哈希表，code 獲取文本驗(yàn)證碼，img 獲取 BufferedImage 圖片對象
     **/
    public static Map<String, Object> generateCodeImage(int n) {
        int width = 100, height = 50;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = image.createGraphics();
        g.setColor(Color.LIGHT_GRAY);
        g.fillRect(0, 0, width, height);
        String chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        Random random = new Random();
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < n; i++) {
            int index = random.nextInt(chars.length());
            char c = chars.charAt(index);
            sb.append(c);
            g.setColor(new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255)));
            g.setFont(new Font("Arial", Font.BOLD, 25));
            g.drawString(Character.toString(c), 20 + i * 15, 25);
        }
        Map<String, Object> res = new HashMap<>();
        res.put("code", sb.toString());
        res.put("img", image);
        return res;
    }
}

@RequestMapping("/captcha")
@RestController
public class CaptchaController {
    @GetMapping("/code/custom")
    public void getCode(HttpServletResponse response) {
        Map<String, Object> map = MyCaptchaUtil.generateCodeImage(5);
        System.out.println(map.get("code"));
        BufferedImage img = (BufferedImage) map.get("img");
        // 設(shè)置響應(yīng)頭，防止緩存
        response.setHeader("Cache-Control", "no-store, no-cache");
        response.setContentType("image/png");
        try {
            ImageIO.write(img, "png", response.getOutputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

<!-- 驗(yàn)證碼模塊 -->
<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-captcha</artifactId>
    <version>5.8.15</version>
</dependency>
<!-- 全部模塊都引入 -->
<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.8.15</version>
</dependency>

// 設(shè)置圖形驗(yàn)證碼的寬和高，同時(shí)生成了驗(yàn)證碼，可以通過 lineCaptcha.getCode() 獲取文本驗(yàn)證碼
LineCaptcha lineCaptcha = CaptchaUtil.createLineCaptcha(200, 100);

// 設(shè)置圖形驗(yàn)證碼的寬、高、驗(yàn)證碼字符數(shù)、干擾元素個(gè)數(shù)
CircleCaptcha captcha = CaptchaUtil.createCircleCaptcha(200, 100, 4, 20);

// 定義圖形驗(yàn)證碼的寬、高、驗(yàn)證碼字符數(shù)、干擾線寬度
ShearCaptcha captcha = CaptchaUtil.createShearCaptcha(200, 100, 4, 4);

@RequestMapping("/captcha")
@RestController
public class CaptchaController {
    @GetMapping("/code/hutool")
    public void getCodeByHutool(HttpServletResponse response) {
        LineCaptcha lineCaptcha = CaptchaUtil.createLineCaptcha(200, 100);
        System.out.println("線段干擾的驗(yàn)證碼：" + lineCaptcha.getCode());
        // 設(shè)置響應(yīng)頭，防止緩存
        response.setHeader("Cache-Control", "no-store, no-cache");
        response.setContentType("image/png");
        try {
            lineCaptcha.write(response.getOutputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

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

package cn.god23bin.demo.config;
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 KaptchaConfig {
    /**
     * 配置生成圖片驗(yàn)證碼的bean
     * @return
     */
    @Bean(name = "kaptchaProducer")
    public DefaultKaptcha getKaptchaBean() {
        DefaultKaptcha defaultKaptcha = new DefaultKaptcha();
        Properties properties = new Properties();
        properties.setProperty("kaptcha.border", "no");
        properties.setProperty("kaptcha.textproducer.font.color", "black");
        properties.setProperty("kaptcha.textproducer.char.space", "4");
        properties.setProperty("kaptcha.textproducer.char.length", "4");
        properties.setProperty("kaptcha.textproducer.char.string", "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789");
        Config config = new Config(properties);
        defaultKaptcha.setConfig(config);
        return defaultKaptcha;
    }
}

// 生成文字驗(yàn)證碼
String text = kaptchaProducer.createText();
// 生成圖片驗(yàn)證碼
BufferedImage image = kaptchaProducer.createImage(text);

@RequestMapping("/captcha")
@RestController
public class CaptchaController {
    @Autowired
    private Producer kaptchaProducer;
    @GetMapping("/code/kaptcha")
    public void getCodeByKaptcha(HttpServletResponse response) {
        // 生成文字驗(yàn)證碼
        String text = kaptchaProducer.createText();
        System.out.println("文字驗(yàn)證碼：" + text);
        // 生成圖片驗(yàn)證碼
        BufferedImage image = kaptchaProducer.createImage(text);
        // 設(shè)置響應(yīng)頭，防止緩存
        response.setHeader("Cache-Control", "no-store, no-cache");
        response.setContentType("image/jpeg");
        try {
            ImageIO.write(image, "jpg", response.getOutputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

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

spring:
  redis:
    host: localhost
    port: 6379
    database: 1
    timeout: 5000

@Configuration
public class RedisConfig extends CachingConfigurerSupport {
    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
        // 大多數(shù)情況，都是選用<String, Object>
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(redisConnectionFactory);
        // 使用JSON的序列化對象，對數(shù)據(jù) key 和 value 進(jìn)行序列化轉(zhuǎn)換
        Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<>(Object.class);
        // ObjectMapper 是 Jackson 的一個(gè)工作類，作用是將 JSON 轉(zhuǎn)成 Java 對象，即反序列化。或?qū)?Java 對象轉(zhuǎn)成 JSON，即序列化
        ObjectMapper mapper = new ObjectMapper();
        // 設(shè)置序列化時(shí)的可見性，第一個(gè)參數(shù)是選擇序列化哪些屬性，比如時(shí)序列化 setter? 還是 filed? 第二個(gè)參數(shù)是選擇哪些修飾符權(quán)限的屬性來序列化，比如 private 或者 public，這里的 any 是指對所有權(quán)限修飾的屬性都可見(可序列化)
        mapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        jackson2JsonRedisSerializer.setObjectMapper(mapper);
        // 設(shè)置 RedisTemplate 模板的序列化方式為 jacksonSeial
        template.setDefaultSerializer(jackson2JsonRedisSerializer);
        return template;
    }
}

@RequestMapping("/captcha")
@RestController
public class CaptchaController {
    @Autowired
    private Producer kaptchaProducer;
    @Autowired
    private RedisTemplate<String, Object> redisTemplate;
    @GetMapping("/code")
    public void getCode(HttpServletRequest request, HttpServletResponse response) {
        // 生成文字驗(yàn)證碼
        String text = kaptchaProducer.createText();
        System.out.println("文字驗(yàn)證碼：" + text);
        // 生成圖片驗(yàn)證碼
        BufferedImage image = kaptchaProducer.createImage(text);
        // 存儲到 Redis 設(shè)置 5 分鐘的過期時(shí)間
        // 約定好存儲的 Key 的命名規(guī)則，這里使用 code_sessionId_type_1 表示圖形驗(yàn)證碼
        // Code_sessionId_Type_1：分為 3 部分，code 表明是驗(yàn)證碼，sessionId 表明是給哪個(gè)用戶的驗(yàn)證碼，type_n 表明驗(yàn)證碼類型，n 為 1 表示圖形驗(yàn)證碼，2 表示短信驗(yàn)證碼，3 表示郵件驗(yàn)證碼
        String key = "code_" + request.getSession().getId() + "_type_1";
        redisTemplate.opsForValue().set(key, text, 5, TimeUnit.SECONDS);
        response.setHeader("Cache-Control", "no-store, no-cache");
        response.setContentType("image/jpeg");
        try {
            ImageIO.write(image, "jpg", response.getOutputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

package cn.god23bin.demo.model.domain.dto;
import lombok.Data;
@Data
public class LoginDTO {
    private String username;
    private String password;
    /**
     * 驗(yàn)證碼
     */
    private String code;
}

@RequestMapping("/user")
@RestController
public class UserController {
    @Autowired
    private RedisTemplate<String, Object> redisTemplate;
    @PostMapping("/login")
    public Result<String> login(@RequestBody LoginDTO loginDTO, HttpServletRequest request) {
        if (!"root".equals(loginDTO.getUsername()) || !"123456".equals(loginDTO.getPassword())) {
            return Result.fail("登錄失敗！賬號或密碼不正確！");
        }
        // 校驗(yàn)用戶輸入的驗(yàn)證碼
        String code = loginDTO.getCode();
        String codeInRedis = (String) redisTemplate.opsForValue().get("code_" + request.getSession().getId() + "_type_1");
        if (!code.equals(codeInRedis)) {
            return Result.fail("驗(yàn)證碼不正確！");
        }
        return Result.ok("登錄成功！");
    }
}