java生成图形验证码

1.需求
提供一个接口，请求接口，返回一个图形验证码

2.Controller接口

   @RequestMapping(value = "/get-verify")
   public void getVerify(HttpServletRequest request, HttpServletResponse response) {
    try {
        //设置相应类型,告诉浏览器输出的内容为图片
        response.setContentType("image/jpeg");
        //设置响应头信息，告诉浏览器不要缓存此内容
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expire", 0);
        RandomValidateCodeUtil randomValidateCode = new RandomValidateCodeUtil();
        //输出验证码图片方法
        randomValidateCode.getRandCode(request, response);
    } catch (Exception e) {
        LOG.error("获取验证码失败>>>>   ", e);
    }
}

3.随机生成验证码的工具类

public class RandomValidateCodeUtil {

private static final Logger LOG = Logger.getLogger(RandomValidateCodeUtil.class);

/**
 * 随机产生数字与字母组合的字符串
 */
private String randString = "0123456789abcdefghijklmnopqrstuvwxyz";

/**
 * 图片宽
 */
private int width = 95;

/**
 * 图片高
 */
private int height = 25;

/**
 * 干扰线数量
 */
private int lineSize = 40;

/**
 * 随机产生字符数量
 */
private int stringNum = 4;

private Random random = new Random();

/**
 * 获得字体
 */
private Font getFont() {
    return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
}

/**
 * 获得颜色
 */
private Color getRandColor(int fc, int bc) {
    if (fc > 255) {
        fc = 255;
    }
    if (bc > 255) {
        bc = 255;
    }
    int r = fc + random.nextInt(bc - fc - 16);
    int g = fc + random.nextInt(bc - fc - 14);
    int b = fc + random.nextInt(bc - fc - 18);
    return new Color(r, g, b);
}

/**
 * 生成随机图片
 */
public void getRandCode(HttpServletRequest request, HttpServletResponse response) {
    HttpSession session = request.getSession();
    // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);

    //产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
    Graphics g = image.getGraphics();
    //图片大小
    g.fillRect(0, 0, width, height);
    //字体大小
    g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
    //字体颜色
    g.setColor(getRandColor(110, 133));
    // 绘制干扰线
    for (int i = 0; i <= lineSize; i++) {
        drowLine(g);
    }
    // 绘制随机字符
    String randomString = "";
    for (int i = 1; i <= stringNum; i++) {
        randomString = drowString(g, randomString, i);
    }
    LOG.info(randomString);
    //将生成的随机字符串保存到session中
    session.removeAttribute(SessionNames.RANDOM_CODE_KEY);
    session.setAttribute(SessionNames.RANDOM_CODE_KEY, randomString);
    g.dispose();
    try {
        // 将内存中的图片通过流动形式输出到客户端
        ImageIO.write(image, "JPEG", response.getOutputStream());
    } catch (Exception e) {
        LOG.error("将内存中的图片通过流动形式输出到客户端失败>>>>   ", e);
    }

}

/**
 * 绘制字符串
 */
private String drowString(Graphics g, String randomString, int i) {
    g.setFont(getFont());
    g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
            .nextInt(121)));
    String rand = String.valueOf(getRandomString(random.nextInt(randString
            .length())));
    randomString += rand;
    g.translate(random.nextInt(3), random.nextInt(3));
    g.drawString(rand, 13 * i, 16);
    return randomString;
}

/**
 * 绘制干扰线
 */
private void drowLine(Graphics g) {
    int x = random.nextInt(width);
    int y = random.nextInt(height);
    int xl = random.nextInt(13);
    int yl = random.nextInt(15);
    g.drawLine(x, y, x + xl, y + yl);
}

/**
 * 获取随机的字符
 */
public String getRandomString(int num) {
    return String.valueOf(randString.charAt(num));
}
}

4.postman测试效果

image.png

5.浏览器展示

image.png