生成随机验证码

来源：互联网发布：shake it of 编辑：程序博客网时间：2024/06/15 19:00
import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.io.IOException;import java.io.OutputStream;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.commons.lang3.math.NumberUtils;import org.apache.commons.lang3.StringUtils;/** * 生成随机验证码 * @author ThinkGem * @version 2014-7-27 */@SuppressWarnings("serial")public class ValidateCodeServlet extends HttpServlet {        public static final String VALIDATE_CODE = "validateCode";        private int w = 70;    private int h = 26;        public ValidateCodeServlet() {        super();    }        public void destroy() {        super.destroy();    }        public static boolean validate(HttpServletRequest request, String validateCode){        String code = (String)request.getSession().getAttribute(VALIDATE_CODE);        return validateCode.toUpperCase().equals(code);    }    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        String validateCode = request.getParameter(VALIDATE_CODE); // AJAX验证，成功返回true        if (StringUtils.isNotBlank(validateCode)){            response.getOutputStream().print(validate(request, validateCode)?"true":"false");        }else{            this.doPost(request, response);        }    }    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        createImage(request,response);    }        private void createImage(HttpServletRequest request,            HttpServletResponse response) throws IOException {                response.setHeader("Pragma", "no-cache");        response.setHeader("Cache-Control", "no-cache");        response.setDateHeader("Expires", 0);        response.setContentType("image/jpeg");                /*         * 得到参数高，宽，都为数字时，则使用设置高宽，否则使用默认值         */        String width = request.getParameter("width");        String height = request.getParameter("height");        if (StringUtils.isNumeric(width) && StringUtils.isNumeric(height)) {            w = NumberUtils.toInt(width);            h = NumberUtils.toInt(height);        }                BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);        Graphics g = image.getGraphics();        /*         * 生成背景         */        createBackground(g);        /*         * 生成字符         */        String s = createCharacter(g);        request.getSession().setAttribute(VALIDATE_CODE, s);        g.dispose();        OutputStream out = response.getOutputStream();        ImageIO.write(image, "JPEG", out);        out.close();    }        private Color getRandColor(int fc,int bc) {        int f = fc;        int b = bc;        Random random=new Random();        if(f>255) {            f=255;        }        if(b>255) {            b=255;        }        return new Color(f+random.nextInt(b-f),f+random.nextInt(b-f),f+random.nextInt(b-f));    }        private void createBackground(Graphics g) {        // 填充背景        g.setColor(getRandColor(220,250));        g.fillRect(0, 0, w, h);        // 加入干扰线条        for (int i = 0; i < 8; i++) {            g.setColor(getRandColor(40,150));            Random random = new Random();            int x = random.nextInt(w);            int y = random.nextInt(h);            int x1 = random.nextInt(w);            int y1 = random.nextInt(h);            g.drawLine(x, y, x1, y1);        }    }    private String createCharacter(Graphics g) {        char[] codeSeq = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J',                'K', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',                'X', 'Y', 'Z', '2', '3', '4', '5', '6', '7', '8', '9' };        String[] fontTypes = {"Arial","Arial Black","AvantGarde Bk BT","Calibri"};        Random random = new Random();        StringBuilder s = new StringBuilder();        for (int i = 0; i < 4; i++) {            String r = String.valueOf(codeSeq[random.nextInt(codeSeq.length)]);//random.nextInt(10));            g.setColor(new Color(50 + random.nextInt(100), 50 + random.nextInt(100), 50 + random.nextInt(100)));            g.setFont(new Font(fontTypes[random.nextInt(fontTypes.length)],Font.BOLD,26));            g.drawString(r, 15 * i + 5, 19 + random.nextInt(8));//            g.drawString(r, i*w/4, h-5);            s.append(r);        }        return s.toString();    }    }
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