JAVA图片验证码

    import java.awt.Color; 
    import java.awt.Font; 
    import java.awt.Graphics2D; 
    import java.awt.RenderingHints; 
    import java.awt.image.BufferedImage; 
    import java.util.Random; 
     
    import org.apache.commons.lang3.StringUtils; 
     
    /**
     * 图片验证码类
     */ 
    public class Captcha { 
        private int width = 100; 
        private int height = 30; 
        private Random random = new Random(); 
        private BufferedImage image; 
        /** 验证码图片上显示的字符 */ 
        private String code; 
        /** 波形的幅度倍数，越大扭曲的程序越高，一般为3 */ 
        private int twistLevel = 2; 
        /** 干扰线数量 */ 
        private int noiseLineNumber = 3; 
        /** 背景色 */ 
        private Color backgroundColor = Color.WHITE; 
        /** 字体颜色 */ 
        // private Color foregroundColor = Color.BLACK; 
        private Color[] colors = { Color.BLUE, Color.RED, Color.GREEN, Color.BLACK, Color.CYAN, Color.MAGENTA }; 
     
        private Color getRandomColor() { 
            return colors[random.nextInt(colors.length)]; 
        } 
     
        /**
         * @param width
         *            - 验证码图片宽度
         * @param height
         *            - 验证码图片高度
         * @param randomStr
         *            - 随机字符串
         * @return
         */ 
        public Captcha generate(int width, int height, String randomStr) { 
            this.width = width; 
            this.height = height; 
            this.code = randomStr; 
            if (StringUtils.isBlank(code)) { 
                throw new RuntimeException("randomStr can not be empty."); 
            } 
            int xWidth = width / (code.length() + 2); 
            int yIndex = height - 4; 
            Graphics2D graphics = graphicsInit(); 
            for (int i = 0; i < code.length(); i++) { 
                // graphics.setColor(foregroundColor); 
                graphics.setColor(getRandomColor()); 
                graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 
                graphics.drawString(code.charAt(i) + "", (i + 1) * xWidth, yIndex); 
            } 
            setBuffImg(disturb()); 
            return this; 
        } 
     
        private Graphics2D graphicsInit() { 
            Graphics2D graphics = buffImgInit().createGraphics(); 
            graphics.setColor(backgroundColor); 
            graphics.fillRect(0, 0, width, height); 
            graphics.setFont(new Font("Fixedsys", Font.ITALIC, height - 2)); 
            graphics.drawRect(0, 0, width - 1, height - 1); 
            return graphics; 
        } 
     
        private BufferedImage buffImgInit() { 
            image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); 
            return image; 
        } 
     
        private BufferedImage disturb() { 
            drawNoiseLine(image.createGraphics()); 
            return twistImage(); 
        } 
     
        private void drawNoiseLine(Graphics2D graphics) { 
            int x = 0; 
            int y = 0; 
            int xl = 0; 
            int yl = 0; 
            for (int i = 0; i < noiseLineNumber; i++) { 
                x = random.nextInt(width * 2 / 3); 
                y = random.nextInt(height * 2 / 3); 
                xl = random.nextInt(width / 2); 
                yl = random.nextInt(height / 2); 
                // graphics.setColor(foregroundColor); 
                graphics.setColor(getRandomColor()); 
                graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 
                graphics.drawLine(x, y, x + xl, y + yl); 
            } 
        } 
     
        private BufferedImage twistImage() { 
            double dMultValue = random.nextInt(9) + twistLevel; 
            double dPhase = random.nextInt(6);// 波形的起始相位，取值区间（0-2＊PI） 
            BufferedImage destBi = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_INT_RGB); 
            Graphics2D graphics = destBi.createGraphics(); 
            graphics.setColor(backgroundColor); 
            graphics.fillRect(0, 0, width, height); 
            for (int i = 0; i < destBi.getWidth(); i++) { 
                for (int j = 0; j < destBi.getHeight(); j++) { 
                    int nOldX = getXPosition4Twist(dPhase, dMultValue, destBi.getHeight(), i, j); 
                    int nOldY = j; 
                    if (nOldX >= 0 && nOldX < destBi.getWidth() && nOldY >= 0 && nOldY < destBi.getHeight()) { 
                        destBi.setRGB(nOldX, nOldY, image.getRGB(i, j)); 
                    } 
                } 
            } 
            return destBi; 
        } 
     
        private int getXPosition4Twist(double dPhase, double dMultValue, int height, int xPosition, int yPosition) { 
            double PI = Math.PI; // 此值越大，扭曲程度越大 
            double dx = (double) (PI * yPosition) / height + dPhase; 
            double dy = Math.sin(dx); 
            return xPosition + (int) (dy * dMultValue); 
        } 
     
        public BufferedImage getImage() { 
            return image; 
        } 
     
        public void setBuffImg(BufferedImage buffImg) { 
            this.image = buffImg; 
        } 
     
        public int getWidth() { 
            return width; 
        } 
     
        public void setWidth(int width) { 
            this.width = width; 
        } 
     
        public int getHeight() { 
            return height; 
        } 
     
        public void setHeight(int height) { 
            this.height = height; 
        } 
     
    } 



使用示例：
Java代码  收藏代码

    String randomStr = RandomStringUtils.randomAlphabetic(4).toLowerCase(); 
    request.getSession().setAttribute(KEY_CAPTCHA, randomStr); 
    BufferedImage bi = new Captcha().generate(200, 50, randomStr).getImage(); 
    ByteArrayOutputStream bos = new ByteArrayOutputStream(); 
    JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(bos); 
    encoder.encode(bi); 
    ImageIO.write(bi, "JPEG", response.getOutputStream());