用servlet生成验证码

        package com.work.core.image;

 

    import java.awt.Color;

    import java.awt.Font;

    import java.awt.Graphics;

    import java.awt.image.BufferedImage;

    import java.io.IOException;

    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 javax.servlet.http.HttpSession;

 

    import org.apache.commons.logging.Log;

    import org.apache.commons.logging.LogFactory;

 

    /**

     * @author wangmj

     * 生成随机的验证码！防止暴利破解。

     */

    public class AuthImage extends HttpServlet {

        private static Log log = LogFactory.getLog(AuthImage.class);

        /**

         *

         */

        private static final long serialVersionUID = 8165458985542870320L;

    //设置图形验证码中的字符串的字体的大小

        private Font mFont = new Font("Arial Black", Font.PLAIN, 16);

 

        public void init() throws ServletException {

            super.init();

        }

 

        /**

         * 生成随机颜色

         * @param fc

         * @param bc

         * @return

         */

        Color getRandColor(int fc, int bc) {

            Random random = new Random();

            if (fc > 255)

                fc = 255;

            if (bc > 255)

                bc = 255;

            int r = fc + random.nextInt(bc - fc);

            int g = fc + random.nextInt(bc - fc);

            int b = fc + random.nextInt(bc - fc);

            return new Color(r, g, b);

        }

 

        /* (non-doc)

         * @see javax.servlet.http.HttpServlet#service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

         */

        public void service(HttpServletRequest request, HttpServletResponse response)

                throws ServletException, IOException {

            //生成相应的service方法

            //阻止生成的页面内容被缓存，保证每次重新生成随机验证码

            response.setHeader("Pragma", "No-cache");

            response.setHeader("Cache-Control", "no-cache");

            response.setDateHeader("Expires", 0);

            response.setContentType("image/jpeg");

    //指定图形验证码图片的大小；

            int width = 80;//宽度

            int height = 20;//高度

 

            BufferedImage image = new BufferedImage(width, height,

                    BufferedImage.TYPE_INT_RGB);

 

    //      准备在图片中绘制内容

            Graphics g = image.getGraphics();

            Random random = new Random();

            g.setColor(getRandColor(200, 250));

            g.fillRect(1, 1, width - 1, height - 1);

            g.setColor(new Color(102, 102, 102));

            g.drawRect(0, 0, width - 1, height - 1);

            g.setFont(mFont);

 

 

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【责编:landy】

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