验证码大全

一、验证码简介

• 使用验证码的作用:防止恶意破解密码、刷票、论坛灌水、刷页、恶意注册、登录
  不使用验证码的问题

  • 使用程序破解某个用户的密码
  • 使用程序在论坛疯狂灌水
  • 使用程序刷票
  • 使用程序暴力实施所有提交数据的行为

    二、随机字符串验证码

• 通过程序随机生成由大写字母、小写字母、数字、汉字组成的字符串

• 优点：生成方便，识别难易程度可调节
• 缺点：识别度不好掌握，识别度高容易被程序识别，识别度低用户体验较差

使用Java实现随机字符串验证码步骤

• 创建画板：new BufferedImage()
• 创建画笔：画板.getGraphics()
• 随机生成内容：不同颜色的字符
• 绘制内容：画笔.drawString()

• 存为图片发送：ImageIO.write(画板，图片类型，输出流) ```java @Component @Slf4j public class RandomCodeUtil { private final Random random = new Random();

  public String randCode(int len) { if (len < 4) {

     len = 4;

  } // 生成字符串 StringBuilder code = new StringBuilder(); for (int i = 0; i < len; i++) {

     String str = "1234567890abcdefghijklmnopqrstuvwxyz";
     code.append(str.charAt(random.nextInt(str.length())));

  } return code.toString(); }

public Color randColor() {
    int r = random.nextInt(256);
    int g = random.nextInt(256);
    int b = random.nextInt(256);
    return new Color(r, g, b);
}
public void createCode(HttpServletRequest request, HttpServletResponse response) throws IOException {
    //    创建画板
    int height = 60;
    int width = 140;
    BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
    //    创建画笔
    Graphics2D pen = img.createGraphics();
    //    生成随机字符串
    String code = randCode(4);
    log.info(code);
    request.getSession().setAttribute("randomCode", code);
    pen.fillRect(0, 0, width, height);
    int fontSize = 14;
    pen.setFont(new Font("微软雅黑", Font.BOLD, fontSize + random.nextInt(5)));
    for (int i = 0; i < code.length(); i++) {
        pen.setColor(randColor());
        pen.drawString(code.charAt(i) + "", 20 + i * fontSize, (fontSize + height) / 2 + random.nextInt(5));
    }
    ServletOutputStream out = response.getOutputStream();
    ImageIO.write(img,"png", out);
    out.flush();
    out.close();
}

}

- controller实现
```java
@GetMapping("/randomCode")
private void randomCode() {
    try {
        randomCodeUtil.createCode(request, response);
    } catch (IOException e) {
        e.printStackTrace();
    }
}
@GetMapping("/checkRandomCode")
private String checkRandomCode(String code) {
    String saveCode = (String) request.getSession().getAttribute("randomCode");
    log.info("randomCode");
    if (saveCode.equalsIgnoreCase(code)) {
        log.info("验证码正确");
        return "验证码正确";
    } else {
        log.info("验证码错误");
        return "验证码错误";
    }
    }

三、算数验证码

@Component
@Slf4j
public class RandomCodeUtil {
    private final Random random = new Random();
    public String randCode(int len) {
        if (len < 4) {
            len = 4;
        }
        //  生成字符串
        StringBuilder code = new StringBuilder();
        for (int i = 0; i < len; i++) {
            String str = "1234567890abcdefghijklmnopqrstuvwxyz";
            code.append(str.charAt(random.nextInt(str.length())));
        }
        return code.toString();
    }
    public Color randColor() {
        int r = random.nextInt(256);
        int g = random.nextInt(256);
        int b = random.nextInt(256);
        return new Color(r, g, b);
    }
    public void createCode(HttpServletRequest request, HttpServletResponse response) throws IOException {
        //    创建画板
        int height = 60;
        int width = 140;
        BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        //    创建画笔
        Graphics2D pen = img.createGraphics();
        //    生成随机字符串
        String code = randCode(4);
        log.info(code);
        request.getSession().setAttribute("randomCode", code);
        pen.fillRect(0, 0, width, height);
        int fontSize = 14;
        pen.setFont(new Font("微软雅黑", Font.BOLD, fontSize + random.nextInt(5)));
        for (int i = 0; i < code.length(); i++) {
            pen.setColor(randColor());
            pen.drawString(code.charAt(i) + "", 20 + i * fontSize, (fontSize + height) / 2 + random.nextInt(5));
        }
        ServletOutputStream out = response.getOutputStream();
        ImageIO.write(img,"png", out);
        out.flush();
        out.close();
    }
}

• controller实现

  @GetMapping("/mathCode")
    private void mathCode() {
        try {
            mathCodeUtil.createCode(request, response);
        } catch (IOException e) {
            log.error("生成验证码错误");
        }
    }
    @GetMapping("/checkMathCode")
    private String checkMathCode(String code) {
        int saveCode = (Integer) request.getSession().getAttribute("mathCode");
        log.info(String.valueOf(saveCode));
        int sendCode = Integer.parseInt(code);
        if (saveCode == sendCode) {
            log.info("验证码正确");
            return "验证码正确";
        } else {
            log.info("验证码错误");
            return "验证码错误";
        }
    }

  四、kaptcha框架验证码

• 优点：实用，根据帮助文档进行配置即可，不用考虑实现细节

  • 添加pom依赖

    <dependency>
           <groupId>com.github.axet</groupId>
           <artifactId>kaptcha</artifactId>
           <version>0.0.9</version>
    </dependency>

  • 实现配置类

    @Configuration
    public class KaptchaConfig {
    @Bean
    public DefaultKaptcha producer(){
       Properties properties = new Properties();
       properties.put("kaptcha.barber","no");
       properties.put("kaptcha.textproducer.font.color","black");
       properties.put("kaptcha.textproducer.char.space","5");
       Config config = new Config(properties);
       DefaultKaptcha defaultKaptcha = new DefaultKaptcha();
       defaultKaptcha.setConfig(config);
       return defaultKaptcha;
    }
    }

  • 写controller接口 ```java @GetMapping(“/captchCode”) private void captchCode() { response.setHeader(“Cache-Control”, “no-store”); response.setContentType(“image/jpeg”); // 文字验证码 String text = producer.createText(); log.info(text); request.getSession().setAttribute(“captchCode”, text); // 图片验证码 BufferedImage image = producer.createImage(text); // 保存验证码到session request.getSession().setAttribute(Constants.KAPTCHA_SESSION_CONFIG_KEY, text); ServletOutputStream outputStream = null; try {

       outputStream = response.getOutputStream();
       ImageIO.write(image, "jpg", outputStream);

    } catch (IOException e) {

       e.printStackTrace();

    } IOUtils.closeQuietly(outputStream); }

@GetMapping("/checkCapchaCode")
private String checkCapchaCode(String code) {
    String saveCode = (String) request.getSession().getAttribute("captchCode");
    log.info(saveCode);
    if (saveCode.equalsIgnoreCase(code)) {
        log.info("验证码正确");
        return "验证码正确";
    } else {
        log.info("验证码错误");
        return "验证码错误";
    }
}

```

五、滑块验证码——阿里云提供

• 整合流程

  • 阿里云控制台搜索云盾，开通验证码服务
  • 新建一个验证码配置，生成一个HTML的demo
  • 根据接入文档，编写调用代码
  • 前台页面调用并验证

    六、图形验证码——腾讯云提供

• 整合流程

  • 登录腾讯验证码接入平台
  • 新建验证码配置
  • 根据接入文档，编写调用代码
  • 前台页面调用并验证