一些实用技术的整理之一：验证码功能的实现

来源：互联网发布：淘宝虚假交易申诉场景编辑：程序博客网时间：2024/05/17 04:06

验证码就是每次访问页面时随机生成的一张图片，里面的内容一般是数字、字母或表达式的随机组合，这个东西蛮有用的，而且也是基本技能之一，所以要把代码贴出来，以留备用~~

校验码有两个比较重要的类：Graphics类和BufferedImage类，详细内容参见API手册~~

以数字校验的实现来吧，下面具体上图~~

新建一个名为JSP_Verify的Dynamic WEB工程，具体的工程目录如下：

其中：image.jsp用于生成随机数字校验码；login.jsp为登录页面；validate.jsp为验证页面了

然后具体实现吧，上代码~~

<%@ page language="java" contentType="text/html; charset=GBK"    pageEncoding="GBK"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=GBK"><script type="text/javascript">function loadimage(){document.getElementById("randImage").src = "image.jsp?"+ Math.random();}</script><title>用户登录</title></head><body><table width="256" border="0" cellpadding="0" cellspacing="0"><!-- DWLayoutTable --><form action="validate.jsp" method="post" name="loginForm"><tr><td width="118" height="22" valign="middle" align="center"><input type="text" name="rand" size="15"></td><td width="138" valign="middle" align="center"><img alt="code..." src="randImage" id="randImage" src="image.jsp" width="60" height="20" border="1" align="absmiddle"></td></tr><tr><td height="36" colspan="2" align="center" valign="middle"><a href="javascript:loadimage();"><font class=pt95>看不清楚点我</font></a></td></tr><tr><td height="36" colspan="2" align="center" valign="middle"><input type="submit" name="login" value="提交"></tr></form></table></body></html>

image.jsp的具体代码如下：

<%@ page language="java" contentType="text/html; charset=GBK"    pageEncoding="GBK"%>    <%@ page import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %><%@ page import="java.io.OutputStream" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=GBK"><title>验证码生成</title></head><%!Color getRandColor(int fc,int bc){Random random = new Random();if (fc > 255)fc = 255;if (bc > 255)bc = 255;int r = fc +random.nextInt(bc - fc);int g = fc +random.nextInt(bc - fc);int b = fc +random.nextInt(bc - fc);return new Color(r, g, b);}%><%try {response.setHeader("Pragma", "No-cache");response.setHeader("Cache-Control", "no-cache");response.setDateHeader("Expires", 0);int width = 60, height = 20;//建立BufferImage对象。指定图片的长度宽度色彩BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);OutputStream os = response.getOutputStream();//取得Graphics对象，用来绘制图像Graphics g = image.getGraphics();//绘制图片背景和文字，释放Graphics对象所占用的资源Random random = new Random();g.setColor(getRandColor(200, 250));g.fillRect(0, 0, width, height);g.setFont(new Font("Times New Roman", Font.PLAIN, 18));g.setColor(getRandColor(160, 200));for (int i=0; i<155; i++) {int x = random.nextInt(width);int y = random.nextInt(height);int x1 = random.nextInt(12);int y1 = random.nextInt(12);g.drawLine(x, y, x+x1, y+y1);}String sRand = "";for (int i=0; i<4; i++) {String rand = String.valueOf(random.nextInt(10));sRand += rand;g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));g.drawString(rand, 13*i+6, 16);}session.setAttribute("rand", sRand);g.dispose();//通过ImageIO对象的write静态方法将图片输出ImageIO.write(image, "JPEG", os);os.flush();os.close();os =null;response.flushBuffer();out.clear();out = pageContext.pushBody();} catch (IllegalStateException e) {System.out.println(e.getMessage());e.printStackTrace();}%><body></body></html>

validate.jsp的具体代码如下：

<%@ page language="java" contentType="text/html; charset=GBK"    pageEncoding="GBK"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=GBK"><title>验证页面</title></head><body><% String rand = (String)session.getAttribute("rand"); String input = request.getParameter("rand"); if(rand.equals(input)){ out.print("<script>alert('验证通过！');</script>"); } else{ out.print("<script>alert('请输入正确的验证码！');location.href='login.jsp';</script>"); } %> </body></html>

然后进login.jsp的代码页面跑跑试试看，错的和对的都试试，如果都行，就OK了~~

第一张是输入正确的校验码：

第二张是输入错误的校验码：

写在最后，上一张博客的校验码验证，不解释~~呵呵

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