数字验证码

<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>
<%@ page contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %>
<%!
Color getRandColor(int cc,int bb)
{
Random random = new Random();
if(cc>255) cc=255;
if(bb>255) bb=255;
int r=cc+random.nextInt(bb-cc);
int g=cc+random.nextInt(bb-cc);
int b=cc+random.nextInt(bb-cc);
return new Color(r,g,b);
} //获取随机颜色
%>
<%
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);

int width=60; //定义验证码图片的长度
int height=20; //定义验证码图片的宽度
BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

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));
//定义字体形式

g.setColor(getRandColor(160,200));
for (int i=0;i<155;i++)
{
int i_x = random.nextInt(width);
int i_y = random.nextInt(height);
int i_xl = random.nextInt(12);
int i_yl = random.nextInt(12);
g.drawLine(i_x,i_y,i_x+i_xl,i_y+i_yl);
}
//用线条画背景

String s_Rand="";
for (int i=0;i<4;i++)
{
String rand=String.valueOf(random.nextInt(10));
s_Rand+=rand;

g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
g.drawString(rand,13*i+6,16);
}
//产生4位随机码

session.setAttribute("rand",s_Rand);
//将验证码存入Session中
g.dispose();
ImageIO.write(image, "JPEG", response.getOutputStream());
out.clear();
out = pageContext.pushBody();
%>