自动生成验证码

来源：互联网发布：淘宝账户被限制为什么编辑：程序博客网时间：2024/05/22 10:50

1：新建一个servlet,名为“imgServlet.java”用于生成带图片的验证码

public class imgServlet extends HttpServlet {    public void doGet(HttpServletRequest request,  HttpServletResponse response)            throws ServletException, IOException {        doPost(request, response);    }    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        /**         * BufferedImage(int width, int height, int imageType)             构造一个类型为预定义图像类型之一的 BufferedImage。         */        BufferedImage bi = new BufferedImage(80,35,BufferedImage.TYPE_INT_RGB);        Graphics g = bi.getGraphics();        //先画一个显示验证码的底板，为红色，大小为80 35        g.setColor(Color.red);        g.fillRect(0, 0, 80, 35);        /**         * 设置验证码         */        char[] arry = "abcdefg1234567890".toCharArray();        Random r = new Random();        StringBuffer sb = new StringBuffer();        for(int i=0; i<4; i++) {            int index = r.nextInt(arry.length);            Font f = new Font(Font.MONOSPACED,Font.BOLD,30);             g.setFont(f);            g.setColor((new Color(r.nextInt(255),r.nextInt(255),r.nextInt(255))));            /**             * drawString(String str, int x, int y)             使用此图形上下文的当前字体和颜色绘制由指定 string 给定的文本。             */            g.drawString(arry[index]+"", i*20, 30);            sb.append(arry[index]);        }//将验证码的内容放在session中        request.getSession().setAttribute("piccode", sb.toString());//图片的输出流，返回到客户端        ImageIO.write(bi, "JPG", response.getOutputStream());    }   }

2：新建一个jsp文件，用于接收验证码图片

<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">    <title>My JSP 'index.jsp' starting page</title>    <meta http-equiv="pragma" content="no-cache">    <meta http-equiv="cache-control" content="no-cache">    <meta http-equiv="expires" content="0">        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">    <meta http-equiv="description" content="This is my page">    <!-- 利用script语句刷新验证码 -->    <script type="text/javascript">        function reLoadCode() {            var time = new Date();            document.getElementById("imagecode").src="imgServlet?id="+time;        }    </script>  </head>  <body>    <form action="login" method="post">       <p align="center">姓名：<input type="text" name="name"/></p>       <p align="center">密码：<input type="password" name="password"/></p>       <p align="center">            <img src="imgServlet" alt="验证码" id="imagecode"/>            <a href="javaScript:reLoadCode()" >看不清</a>       </p>       <P align="center">验证码：<input type="text" name="imgcode"/></P>        <p align="center"><input type="submit" value="登录"><input type="reset" value="重置"></p>     </form>  </body></html>

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