简单java验证码的实现

叁歲伎倆 2022-04-18 04:15 214阅读 0赞

# 简单java验证码的实现 #

### 验证码效果 ###

*  ![NWgd3Kv.jpg][]

### Java方法形式展示 ###

public static String getIdentifyCode(HttpServletResponse response) {
        // 使用java图形界面技术绘制一张图片
        int charNum = 4;
        int width = 30 * 4;
        int height = 30;
        // 1. 创建一张内存图片
        BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    
        // 2.获得绘图对象
        Graphics graphics = bufferedImage.getGraphics();
    
        // 3、绘制背景颜色
        graphics.setColor(Color.YELLOW);
        graphics.fillRect(0, 0, width, height);
    
        // 4、绘制图片边框
        graphics.setColor(Color.BLUE);
        graphics.drawRect(0, 0, width - 1, height - 1);
    
        // 5、输出验证码内容
        graphics.setColor(Color.RED);
        graphics.setFont(new Font("宋体", Font.BOLD, 20));
    
        // 随机输出4个字符
        Graphics2D graphics2d = (Graphics2D) graphics;
        String s = "0123456789";
        Random random = new Random();
        // session中要用到
        String msg = "";
        int x = 5;
        for (int i = 0; i < 4; i++) {
            int index = random.nextInt(10);
            String content = String.valueOf(s.charAt(index));
            msg += content;
            double theta = random.nextInt(45) * Math.PI / 180;
            // 让字体扭曲
            graphics2d.rotate(theta, x, 18);
            graphics2d.drawString(content, x, 18);
            graphics2d.rotate(-theta, x, 18);
            x += 30;
        }
    
        // 6、绘制干扰线
        graphics.setColor(Color.GRAY);
        for (int i = 0; i < 5; i++) {
            int x1 = random.nextInt(width);
            int x2 = random.nextInt(width);
    
            int y1 = random.nextInt(height);
            int y2 = random.nextInt(height);
            graphics.drawLine(x1, y1, x2, y2);
        }
    
        // 释放资源
        graphics.dispose();
    
        // 图片输出 ImageIO
        try {
            ImageIO.write(bufferedImage, "jpg", response.getOutputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
        return msg;
    }

### 注意实现 ###

1.  写完的工具类通过控制类来调用
2.  调用参数response进行验证码结果的展示到浏览器上

[NWgd3Kv.jpg]: https://i.imgur.com/NWgd3Kv.jpg