JSP制作简单“验证码”
用JSP写个简单的“验证码”
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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@page import="java.awt.image.BufferedImage"%><%@page import="java.awt.Graphics"%><%@page import="java.awt.Color"%><%@page import="java.io.OutputStream"%><%@page import="com.sun.image.codec.jpeg.JPEGImageEncoder"%><%@page import="com.sun.image.codec.jpeg.JPEGCodec"%><%@page import="java.awt.Font"%><%String path = request.getContextPath();String basePath = request.getScheme() + "://"+ request.getServerName() + ":" + request.getServerPort()+ path + "/";char[] mapTable = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I','J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V','W', 'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7','8', '9' };// 取随机产生的认证码 String strEnsure = "";// 4代表4位验证码 for (int i = 0; i < 4; ++i) {strEnsure += mapTable[(int) (mapTable.length * Math.random())];}session.setAttribute("strEnsure", strEnsure);response.setContentType("image/jpeg");// 图片的内存映像BufferedImage image = new BufferedImage(70, 24,BufferedImage.TYPE_INT_RGB);Random r = new Random();// 获得画笔对象Graphics g = image.getGraphics();g.setColor(new Color(r.nextInt(255), r.nextInt(255), r.nextInt(255)));g.fillRect(0, 0, 70, 24);g.setColor(new Color(0, 0, 0));g.setFont(new Font("Atlantic Inline", Font.PLAIN, 18));g.drawString(strEnsure, 11, 18);g.drawLine(r.nextInt(60), r.nextInt(20), r.nextInt(60), r.nextInt(20));// 压缩成jpeg格式OutputStream os = response.getOutputStream();JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(os);// 把BufferedImage对象中的图像信息编码后// 向创建该对象(encoder)时指定的输出流输出encoder.encode(image);out.clear();out = pageContext.pushBody();%>?