<%@ page contentType="image/jpeg" import="java.awt.*,
java.awt.image.*,java.util.*,javax.imageio.*" pageEncoding="GB2312"%>
<%
// 在内存中创建图象
int width=60, height=20;
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
Graphics g = image.getGraphics();
// 设定背景色
g.setColor(new Color(0xDCDCDC));
g.fillRect(0, 0, width, height);
//画边框
g.setColor(Color.black);
g.drawRect(0,0,width-1,height-1);
// 随机产生的认证码(4位数字)
String rand =""+ (Math.random()*10000);
rand = rand.substring(0,rand.indexOf("."));
System.out.println("rand:"+rand);
switch(rand.length())
{
case 1: rand = rand+"000"; break;
case 2: rand = rand+"00"; break;
case 3: rand = rand+"0"; break;
default: rand = rand.substring(0,4); break;
}
System.out.println("rand:"+rand);
// 将认证码存入SESSION
session.setAttribute("rand",rand);
// 将认证码显示到图象中
g.setColor(Color.black);
Integer tempNumber = new Integer(rand);
String numberStr = tempNumber.toString();
g.setFont(new Font("Atlantic Inline",Font.PLAIN,18));
String Str = numberStr.substring(0,1);
g.drawString(Str,8,17);
Str = numberStr.substring(1,2);
g.drawString(Str,20,15);
Str = numberStr.substring(2,3);
g.drawString(Str,35,18);
Str = numberStr.substring(3,4);
g.drawString(Str,45,15);
// 随机产生88个干扰点,使图象中的认证码不易被其它程序探测到
Random random = new Random();
for (int i=0;i<20;i++)
{
int x = random.nextInt(width);
int y = random.nextInt(height);
g.drawOval(x,y,0,0);
}
// 图象生效
g.dispose();
// 输出图象到页面
ImageIO.write(image, "JPEG",response.getOutputStream());
//在页面上调用 <img src="/yourPath/checkNum.jsp" />
out . clear();
out = pageContext.pushBody();
%>测试页面:<form action="" name="myform">
<img name="image" src="code.jsp" >
<a href="javascript:refresh()">看不清?换一张</a>
<div>
<input type="text" name="code" onblur="fun_out()" >
</div>
</form>
<script type="text/javascript">
function refresh(){
document.myform.image.src = "code.jsp?param="+Math.random();
}
function fun_out(){
String code=(String)session.getAttribute("rand");
alert(code);
}
</script>
java.awt.image.*,java.util.*,javax.imageio.*" pageEncoding="GB2312"%>
<%
// 在内存中创建图象
int width=60, height=20;
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
Graphics g = image.getGraphics();
// 设定背景色
g.setColor(new Color(0xDCDCDC));
g.fillRect(0, 0, width, height);
//画边框
g.setColor(Color.black);
g.drawRect(0,0,width-1,height-1);
// 随机产生的认证码(4位数字)
String rand =""+ (Math.random()*10000);
rand = rand.substring(0,rand.indexOf("."));
System.out.println("rand:"+rand);
switch(rand.length())
{
case 1: rand = rand+"000"; break;
case 2: rand = rand+"00"; break;
case 3: rand = rand+"0"; break;
default: rand = rand.substring(0,4); break;
}
System.out.println("rand:"+rand);
// 将认证码存入SESSION
session.setAttribute("rand",rand);
// 将认证码显示到图象中
g.setColor(Color.black);
Integer tempNumber = new Integer(rand);
String numberStr = tempNumber.toString();
g.setFont(new Font("Atlantic Inline",Font.PLAIN,18));
String Str = numberStr.substring(0,1);
g.drawString(Str,8,17);
Str = numberStr.substring(1,2);
g.drawString(Str,20,15);
Str = numberStr.substring(2,3);
g.drawString(Str,35,18);
Str = numberStr.substring(3,4);
g.drawString(Str,45,15);
// 随机产生88个干扰点,使图象中的认证码不易被其它程序探测到
Random random = new Random();
for (int i=0;i<20;i++)
{
int x = random.nextInt(width);
int y = random.nextInt(height);
g.drawOval(x,y,0,0);
}
// 图象生效
g.dispose();
// 输出图象到页面
ImageIO.write(image, "JPEG",response.getOutputStream());
//在页面上调用 <img src="/yourPath/checkNum.jsp" />
out . clear();
out = pageContext.pushBody();
%>测试页面:<form action="" name="myform">
<img name="image" src="code.jsp" >
<a href="javascript:refresh()">看不清?换一张</a>
<div>
<input type="text" name="code" onblur="fun_out()" >
</div>
</form>
<script type="text/javascript">
function refresh(){
document.myform.image.src = "code.jsp?param="+Math.random();
}
function fun_out(){
String code=(String)session.getAttribute("rand");
alert(code);
}
</script>
解决方案 »
- CKeditor land.contextmenu.options 为空或不是对象
- struts validation 提示信息有误
- 最近在学习struts遇到了一些问题 求助!!(在线等!急急急!!!)
- 2个表单独的映射都能成功,但是其中一个表加入另一张表的多对一映射就出错。求救
- 请问在Filter中有没有办法能获取ServletConfig对象?
- Spring发送邮件问题
- 会者不难,请高手指教!!! servlet中文处理 ,顺利解决者给 200分重奖
- 请说出您的看法:jsp+bean+html的封装
- 请各位高手帮我看看为什么这段javascript为什么会出错?
- HTML5+Javaweb项目的开发,求大神指教!!!!!!!!!!
- apache-FtpServer不能上传/新建中文名文件,文件夹
- 在ijetty上发布war包时,提示一个错误Servlet Not Initialized?
给你一个demo
你就能搞定了
这句话是个啥?你打算用JavaScript取出服务器端的session信息?这是不行滴。
你只能是提交后,再服务器端取出session信息再进行比较判断。