JAVA验证码

来源：互联网发布：马新贻知乎编辑：程序博客网时间：2024/05/18 02:49
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><%@page import="java.awt.image.BufferedImage"%><%@page import="java.awt.Graphics2D"%><%@page import="java.awt.Color"%><%@page import="java.awt.Font"%><%@page import="javax.imageio.ImageIO"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>My JSP 'code.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"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><%//验证码图片的宽度。Integer width = 105;//验证码图片的高度。Integer height = 30;//验证码字符个数Integer codeCount = 4;//Integer xx = width / (codeCount + 1);//字体高度Integer fontHeight = height - 2;Integer codeY = height - 4;char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H','I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T','U', 'V', 'W', 'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5','6', '7', '8', '9' };// 定义图像bufferBufferedImage buffImg = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);Graphics2D gd = buffImg.createGraphics();// 创建一个随机数生成器类Random random = new Random();// 将图像填充为白色gd.setColor(Color.WHITE);gd.fillRect(0, 0, width, height);// 创建字体，字体的大小应该根据图片的高度来定。Font font = new Font("Fixedsys", Font.PLAIN, fontHeight);// 设置字体。gd.setFont(font);// 画边框。gd.setColor(Color.BLACK);gd.drawRect(0, 0, width - 1, height - 1);gd.setColor(Color.YELLOW);gd.drawRect(1, 1, width - 1, height - 1);gd.drawRect(0, 0, width - 2, height - 2);//随机产生3条干扰线，使图象中的认证码不易被其它程序探测到,干扰线太明显则会导致用户无法看清验证码gd.setColor(Color.GRAY);for (int i = 0; i < 3; i++) {int x = random.nextInt(width);int y = random.nextInt(height);int xl = random.nextInt(12);int yl = random.nextInt(12);gd.drawLine(x, y, x + xl, y + yl);}// randomCode用于保存随机产生的验证码。StringBuffer randomCode = new StringBuffer();int red = 0, green = 0, blue = 0;// 随机产生codeCount数字的验证码。for (int i = 0; i < codeCount; i++) {// 得到随机产生的验证码数字。String strRand = String.valueOf(codeSequence[random.nextInt(36)]);// 产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同。red = random.nextInt(255);green = random.nextInt(255);blue = random.nextInt(255);// 用随机产生的颜色将验证码绘制到图像中。gd.setColor(new Color(red, green, blue));gd.drawString(strRand, (i * xx) + xx / 2, codeY);// 将产生的四个随机数组合在一起。randomCode.append(strRand);}// 将四位数字的验证码保存到Session中。session.setAttribute("validateCode", randomCode.toString());// 禁止图像缓存。response.setHeader("Pragma", "no-cache");response.setHeader("Cache-Control", "no-cache");response.setDateHeader("Expires", 0);response.setContentType("image/jpeg");// 将图像输出到Servlet输出流中。ServletOutputStream sos = response.getOutputStream();ImageIO.write(buffImg, "jpeg", sos);sos.close();out.clear();out = pageContext.pushBody();%></body></html>