JSP验证码大全之数字验证码

最新推荐文章于 2017-10-02 23:02:16 发布

我是程序猿小张

最新推荐文章于 2017-10-02 23:02:16 发布

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分类专栏： jsp

本文链接：https://blog.youkuaiyun.com/zs_453898875/article/details/23038291

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image.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page  import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %>
<%@ page import="java.io.OutputStream" %>
<%!
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;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
OutputStream os=response.getOutputStream();
Graphics g = image.getGraphics();
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 xl = random.nextInt(12);
int yl = random.nextInt(12);
g.drawLine(x,y,x+xl,y+yl);
}
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();

ImageIO.write(image, "JPEG",os);

//注意看以下几句的使用
os.flush();
os.close();
os=null;
response.flushBuffer();
out.clear();
out = pageContext.pushBody();
}
catch(IllegalStateException e)
{
System.out.println(e.getMessage());
e.printStackTrace();
}%>

<%@ page contentType="text/html;charset=utf-8"%>
<%@ page language="java" import="java.sql.*" errorPage=""%>
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
		<title>用户登录</title>
		<script language="javascript">
	function loadimage() {
		document.getElementById("randImage").src = "image.jsp?" + Math.random();
	}
</script>
	</head>
	<body>
		<table width="256" border="0" cellpadding="0" cellspacing="0">
			<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..." name="randImage" id="randImage" src="image.jsp"
							onclick="loadimage()" 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>看不清点我</font>
						</a>
					</td>
				</tr>
				<tr>
					<td height="36" colspan="2" align="center" valign="middle">
						<input type="submit" name="login" value="提交">
					</td>
				</tr>
			</form>
		</table>
	</body>
</html>

validate.jsp

<%@ page contentType="text/html; charset=utf-8" language="java" import="java.sql.*" errorPage="" %> 
<% 
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>"); 
} 
%>