javaWeb购物商城设计---验证码

验证码采用servlet进行设计。
CheckCode.java:https://github.com/imcy/webshop/blob/master/src/com/tools/CheckCode.java
login_check.jsp:https://github.com/imcy/webshop/blob/master/WebContent/front/login_check.jsp

servlet类名称为CheckCode:

package com.tools;import java.awt.*;import java.awt.geom.AffineTransform;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.*;/** * * @author administrator */public class CheckCode extends HttpServlet {    public CheckCode() {        super();    }    // 获取随机颜色    public Color getRandColor(int s, int e) {        Random random = new Random();        if (s > 255) s = 255;        if (e > 255) e = 255;        int r = s + random.nextInt(e - s);      //随机生成RGB颜色中的r值        int g = s + random.nextInt(e - s);      //随机生成RGB颜色中的g值        int b = s + random.nextInt(e - s);      //随机生成RGB颜色中的b值        return new Color(r, g, b);    }    public void service(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        response.setHeader("Pragma", "No-cache");        response.setHeader("Cache-Control", "No-cache");        response.setDateHeader("Expires", 0);        // 指定生成的响应是图片        response.setContentType("image/jpeg");        int width = 116;            //指定验证码的宽度        int height = 33;            //指定验证码的高度        BufferedImage image = new BufferedImage(width, height,                BufferedImage.TYPE_INT_RGB);        Graphics g = image.getGraphics();       //获取Graphics类的对象        Random random = new Random();               //实例化一个Random对象        Font mFont = new Font("宋体", Font.BOLD, 22);   //通过Font构造字体        g.fillRect(0, 0, width, height);                //绘制验证码背景        g.setFont(mFont);           //设置字体        g.setColor(getRandColor(180, 200));     //设置颜色        // 画随机的线条        for (int i = 0; i < 100; i++) {            int x = random.nextInt(width - 1);            int y = random.nextInt(height - 1);            int x1 = random.nextInt(3) + 1;            int y1 = random.nextInt(6) + 1;            g.drawLine(x, y, x + x1, y + y1);       //绘制直线        }        /**************************画一条折线********************************/               BasicStroke bs=new BasicStroke(2f,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL); //创建一个供画笔选择线条粗细的对象        Graphics2D g2d = (Graphics2D) g;    //通过Graphics类的对象创建一个Graphics2D类的对象        g2d.setStroke(bs);                  //改变线条的粗细        g.setColor(Color.GRAY);     //设置当前颜色为预定义颜色中的灰色        int lineNumber=4;       //指定端点的个数        int[] xPoints=new int[lineNumber];      //定义保存x轴坐标的数组        int[] yPoints=new int[lineNumber];      //定义保存x轴坐标的数组        //通过循环为x轴坐标和y轴坐标的数组赋值        for(int j=0;j<lineNumber;j++){            xPoints[j]=random.nextInt(width - 1);            yPoints[j]=random.nextInt(height - 1);        }        g.drawPolyline(xPoints, yPoints,lineNumber);    //绘制折线        /*******************************************************************/        String sRand = "";        // 输出随机的验证文字         for (int i = 0; i < 4; i++) {            char ctmp = (char)(random.nextInt(26) + 65);    //生成A~Z的字母            sRand += ctmp;            Color color = new Color(20 + random.nextInt(110), 20 + random                    .nextInt(110), 20 + random.nextInt(110));            g.setColor(color);              //设置颜色            /** **随机缩放文字并将文字旋转指定角度* */            // 将文字旋转指定角度            Graphics2D g2d_word = (Graphics2D) g;            AffineTransform trans = new AffineTransform();            trans.rotate(random.nextInt(45) * 3.14 / 180, 22 * i + 8, 7);            // 缩放文字            float scaleSize = random.nextFloat() +0.8f;            if (scaleSize > 1f) scaleSize = 1f;            trans.scale(scaleSize, scaleSize);          //进行缩放            g2d_word.setTransform(trans);            /** ********************* */            g.drawString(String.valueOf(ctmp), width/6 * i+23, height/2);        }        // 将生成的验证码保存到Session中        HttpSession session = request.getSession(true);        session.setAttribute("randCheckCode", sRand);        g.dispose();        ImageIO.write(image, "JPEG", response.getOutputStream());    }        public void destroy() {        super.destroy();    }    public void init() throws ServletException {        super.init();    }}

前端界面的显示

<img src="../CheckCode" name="img_checkCode" onClick="myReload()"                                            width="116" height="43" class="img_checkcode" id="img_checkCode" />

点击重新生成验证码的myReload()方法：

<script language="javascript">        //刷新验证码        function myReload() {            document.getElementById("img_checkCode").src = document                    .getElementById("img_checkCode").src + "?nocache=" + new Date().getTime();        }    </script>

web.xml配置

 <servlet>    <servlet-name>CheckCode</servlet-name>    <servlet-class>com.tools.CheckCode</servlet-class>  </servlet>  <servlet-mapping>    <servlet-name>CheckCode</servlet-name>    <url-pattern>/CheckCode</url-pattern>  </servlet-mapping>

显示结果：

验证码判断

验证码判断时取设置验证码时写入Session的Attribute:randCheckCode与输入验证码对比。

HttpSession session = request.getSession(true);
session.setAttribute(“randCheckCode”, sRand);

点击登录将跳转到loginCheck.jsp中，进行判断，在loginCheck.jsp的<body></body>中加入：

if(checkCode.equals(session.getAttribute("randCheckCode").toString())){            //验证码正确的操作        }else {            out.println("<script language='javascript'>alert('您输入的验证码错误!');history.back();</script>");        }