JSP生成验证码

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废话不说，直接上代码了。
validate.jsp

<%@ page language="java"    import="java.awt.*"    import="java.awt.image.BufferedImage"    import="java.util.*"    import="javax.imageio.ImageIO"      pageEncoding="UTF-8"%><%    response.setHeader("Cache-Control","no-cache");     // 在内存中创建图象     int width = 60, height = 20;    BufferedImage image = new BufferedImage(width, height,        BufferedImage.TYPE_INT_RGB);    //获取画笔    Graphics g = image.getGraphics();    //设定背景色     g.setColor(new Color(200, 200, 200));    g.fillRect(0, 0, width, height);    //取随机产生的验证码(4位数字)     Random rnd = new Random();    int randNum = rnd.nextInt(8999) + 1000;    String randStr = String.valueOf(randNum);    //将验证码存入session    session.setAttribute("randStr", randStr);    //将验证码显示到图象中     g.setColor(Color.black);    g.setFont(new Font("", Font.PLAIN, 20));    g.drawString(randStr, 10, 17);    // 随机产生100个干扰点，使图象中的验证码不易被其他程序探测到     for (int i = 0; i < 100; i++){        int x = rnd.nextInt(width);        int y = rnd.nextInt(height);        g.drawOval(x, y, 1, 1);    }    // 输出图象到页面     ImageIO.write(image, "JPEG", response.getOutputStream());    out.clear();    out = pageContext.pushBody();%>

只需要在html文件中引用：<a href="validate.jsp">即可

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