验证码生成

yudilan6

于 2019-09-24 13:11:17 发布

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本文链接：https://blog.youkuaiyun.com/yudilan6/article/details/101278326

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本文介绍了一个Java类CaptchaService，用于生成包含随机字符的验证码图片，并将其转换为Base64编码字符串。该类使用了多种颜色和干扰线来增强验证码的安全性。

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public class CaptchaService {
    private  int width = 90;
    private  int height = 20;
    private  int codeLength = 6;
    private  int xx =11;
    private  int fontHeight = 18;
    private  int codeY = 16;
    private  char[] codes = {'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'};

    public  Map<String,Object> generateCodeAndPic() throws IOException {
        BufferedImage bufferedImage = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
        Graphics gp = bufferedImage.getGraphics();
        Random random = new Random();
        gp.setColor(Color.WHITE);//图片背景：白色
        gp.fillRect(0,0,width,height);
        Font font = new Font("黑体",Font.BOLD,fontHeight);
        gp.setFont(font);

        gp.setColor(Color.BLUE);//边框设置为蓝色
        gp.drawRect(0,0,width - 1,height - 1);

        gp.setColor(Color.RED);//干扰线设置为红色
        for(int i = 0;i < 20; i++){
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int x1 = random.nextInt(15);
            int y1 = random.nextInt(15);
            gp.drawLine(x, y ,x + x1,y + y1);
        }
        StringBuffer randomCode = new StringBuffer();
        int red  = 0,green = 0,blue = 0;

        for (int i = 0;i<codeLength;i++){
            String code = String.valueOf(codes[random.nextInt(36)]);
            red = random.nextInt(255);
            green = random.nextInt(255);
            blue = random.nextInt(255);
            gp.setColor(new Color(red,green,blue));//验证码颜色随机
            gp.drawString(code,(i +1)* xx,codeY);
            randomCode.append(code);
        }
        Map<String,Object> map = new HashMap<>();
        map.put("code",randomCode);
        map.put("codePic",bufferedImage);
        map.put("base64",convertToBase64(bufferedImage));
        return map;
    }

    private  String convertToBase64(BufferedImage image) throws IOException {
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        ImageIO.write(image,"jpg",stream);
        byte[] bytes = stream.toByteArray();
        BASE64Encoder encoder = new BASE64Encoder();
        String encode = encoder.encode(bytes);
        stream.close();
        return encode;
    }
/*
    public static void main(String[] args) throws IOException {
        OutputStream out = new FileOutputStream("F://img/" + System.currentTimeMillis()+".jpg");
       CaptchaService c = new CaptchaService();
        Map<String,Object> map = c.generateCodeAndPic();
        ImageIO.write((RenderedImage) map.get("codePic"),"jpeg",out);
        System.out.println("验证码："+map.get("code"));

    }*/

  
}