jsp数字验证码防暴力破解
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2008-04-25
11:58:04
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纯数字验证码
经过验证,可行
四位:
Code.jsp:
<%@ page contentType="image/jpeg" import="java.awt.*,
java.awt.image.*,java.util.*,javax.imageio.*" %>
<%
// 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("."));
switch(rand.length())
{
case 1: rand = "000"+rand; break;
case 2: rand = "00"+rand; break;
case 3: rand = "0"+rand; break;
default: rand = rand.substring(0,4); break;
}
// 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);
资源评论
luxiangping_lxp2017-12-05好东西，正好用到
intofirehr2014-05-30好东西，正好用到
