Java实现图片验证码

代码实现

public static final int WIDTH = 120;
/**
 * 图片高度：50px
 */
public static final int HEIGHT = 50;
/**
 * 处理图片验证码方法
 *
 * @param request
 * @param response
 */
@RequestMapping(value="/jcaptcha/captcha")
public void handleCaptchaRequest(HttpServletRequest request, HttpServletResponse response) {
        //生成6位随机验证码
        String captcha = this.getRandomCode(3);
    try {
        //创建字节数组输出流
        ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
        //创建图片缓存对象,BufferedImage.TYPE_INT_RGB ： 表示一个图像，该图像具有整数像素的 8 位 RGB 颜色
        BufferedImage bufferedImage = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
        //获取图片的画布
        Graphics graphics = bufferedImage.getGraphics();
        //设置画布背景色
        graphics.setColor(Color.GREEN);
        //设置画布填充区域
        graphics.fillRect(0, 0, WIDTH, HEIGHT);
        //边框区域
        graphics.drawRect(1, 1, WIDTH - 2, HEIGHT - 2);
        //设置字体颜色
        graphics.setColor(Color.BLACK);
        //设置字体样式
        graphics.setFont(new Font("微软雅黑", Font.ITALIC, 32));
        //填充数据
        graphics.drawString(captcha, 10, 38);
        //将生成的验证码存放到session中
        request.getSession().setAttribute(Constants.CAPTCHA, captcha);

        ImageIO.write(bufferedImage, "jpeg", jpegOutputStream);
        byte[] captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
        //将验证码输出到页面
        response.setHeader("Cache-Control", "no-store");
        response.setHeader("Pragma", "no-cache");
        response.setDateHeader("Expires", 0L);
        response.setContentType("image/jpeg");
        ServletOutputStream respOs = response.getOutputStream();
        respOs.write(captchaChallengeAsJpeg);
        respOs.flush();
        respOs.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}
/**
 * 生成0-9，a-z,A-Z的随机字符串
 * @param count
 * @return
 */
private String getRandomCode(int count) {
    String[] array = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","0","1","2","3","4","5","6","7","8","9"};

    StringBuilder result = new StringBuilder();

    for (int i = 0; i < count; i++) {
        //生成一个下标0-61之间一个整数
        int index = (int) Math.round(Math.random() * 61);
        //从array数组中获取该下标字符放到result中
        result.append(array[index]);
    }
    return result.toString();
}