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验证码 jsp代码

2009-03-03 15:19 423 查看
login.jsp

<%@ page contentType="text/html;charset=gb2312" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>认证码输入页面</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache">
<META HTTP-EQUIV="Expires" CONTENT="0">
<script type="text/javascript">
function change(){
document.getElementById("code").innerHTML="<img align='absmiddle' border=0 src='code.jsp'>";
}
</script>
</head>
<body>
<form method=post action="check.jsp">
<table>
<tr>
<td align=left>系统产生的认证码:</td>
<td id="code"><img align='absmiddle' border=0 src="code.jsp"></img></td>
<td><a href="#" onclick="change()">看不清,换一张!</a></td>
</tr>
<tr>
<td align=left>输入上面的认证码:</td>
<td><input type=text name=rand maxlength=5 size=5 value=""></td>
</tr>
<tr>
<td colspan=2 align=center><input type=submit value="提交检测"></td>
</tr>
</form>
</body>
</html>

code.jsp

<%@ page import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*"%>
<%@ page import="java.io.OutputStream"%>
<%@ page pageEncoding="UTF-8"%>
<%!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 = 85, height = 20;
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
OutputStream os = response.getOutputStream();
Graphics g = image.getGraphics();
Random random = new Random();
//设置背景和大小
g.setColor(getRandColor(200, 250));
g.fillRect(0, 0, width, height);
//设置字体和颜色
g.setFont(new Font("Times New Roman", Font.PLAIN, 20));
g.setColor(getRandColor(120, 200));
for (int i = 0; i < 155; i++) {
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(5);
int yl = random.nextInt(5);
g.drawLine(x, y, x + xl, y + yl);
}
String sRand = "";
for (int i = 0; i < 5; i++) {
String chose="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
String rand = String.valueOf(chose.charAt(random.nextInt(chose.length())));
sRand += rand;
g.setColor(new Color(20 + random.nextInt(110), 20 + random
.nextInt(110), 20 + random.nextInt(110)));
g.drawString(rand, 15 * i + 6, 16);
}
session.setAttribute("rand", sRand);
g.dispose();

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();
}
%>

check.jsp

<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<html>
<head>
<title>认证码验证页面</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<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.equalsIgnoreCase(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>
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