JSP校验码，包括数字和字母
code.jsp页面用于生成校验码图片，代码如下：
<%@ page language="java" pageEncoding="UTF-8"%> <%@ page contentType="image/jpeg" import="java.awt.*, java.awt.image.*,java.util.*,javax.imageio.*" %> <%! //create by smallnest //email: [email protected] //website:www.kuaff.com //生成随机颜色 Color getRandColor(Random random,int fc,int bc) { 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); } %> <% // 设置图片的长宽 int width=176, height=30; //设置备选字符，剔除一些不雅的字符 String base = "abcdefghijklmnopqrstuvwxyz1234567890"; //备选字符的长度 int length = base.length(); //创建内存图像 BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 获取图形上下文 Graphics g = image.getGraphics(); //创建随机类的实例 Random random = new Random(); // 设定图像背景色(因为是做背景，所以偏淡) g.setColor(getRandColor(random,200,250)); g.fillRect(0, 0, width, height); //备选字体 String[] fontTypes = {"\u5b8b\u4f53","\u65b0\u5b8b\u4f53","\u9ed1\u4f53","\u6977\u4f53","\u96b6\u4e66"}; int fontTypesLength = fontTypes.length; //在图片背景上增加噪点 g.setColor(getRandColor(random,160,200)); g.setFont(new Font("Times New Roman",Font.PLAIN,14)); for (int i=0;i<6;i++) { g.drawString("*********************************************",0,5*(i+2)); } //保存生成的字符串 String sRand=""; for (int i=0;i<6;i++) { int start = random.nextInt(length); String rand=base.substring(start,start+1); sRand+=rand; //设置字体的颜色 g.setColor(getRandColor(random,10,150)); //设置字体 g.setFont(new Font(fontTypes[random.nextInt(fontTypesLength)],Font.BOLD,18 + random.nextInt(6))); //将此字符画到图片上 g.drawString(rand,24*i+ 10 + random.nextInt(8),24); } //将认证码存入session session.setAttribute("rand",sRand); g.dispose(); //输出图象到页面 ImageIO.write(image, "JPEG", response.getOutputStream()); out.clear(); out = pageContext.pushBody(); %>
login.jsp用于访问的页面，校验码图片来自于code.jsp，form表单提交到check.jsp，代码如下：
<%@ page contentType="text/html;charset=UTF-8" %> <% 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> <title>认证码输入页面</title> <META HTTP-EQUIV="Pragma" CONTENT="no-cache"> <META HTTP-EQUIV="Cache-Control" CONTENT="no-cache"> <META HTTP-EQUIV="Expires" CONTENT="0"> </head> <body> <form method="post" action="check.jsp"> <table> <tr> <td align=left>系统产生的认证码：</td> <td><img border=0 src="<%=basePath%>code.jsp"></td> </tr> <tr> <td align=left>输入上面的认证码：</td> <td><input type=text name=rand value=""></td> </tr> <tr> <td colspan=2 align=center><input type=submit value="提交检测"></td> </tr> </table> </form> </body> </html>
check.jsp用于检验所输入校验码是否正确，代码如下：
<%@ page language="java" pageEncoding="UTF-8"%>
<html>
<head>
<title>认证码验证页面</title>
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache">
<META HTTP-EQUIV="Expires" CONTENT="0">
</head>
<body>
<%
String rand = (String)session.getAttribute("rand");
String input = request.getParameter("rand");
%>
系统产生的认证码为： <%= rand %><br>
您输入的认证码为： <%= input %><br>
<br>
<%
if (rand.equals(input)) {
%>
<font color=green>输入相同，认证成功！</font>
<%
} else {
%>
<font color=red>输入不同，认证失败！</font>
<%
}
%>
</body>
</html>