神马文学网jsp验证码
来源：百度文库 编辑：神马文学网 时间：2024/04/28 18:29:31
<%@ page contentType="image/jpeg"pageEncoding="gb2312"%>
<%@ page import="java.awt.*,java.awt.image.*"%>
<%@ page import="java.util.*,javax.imageio.*"%>
<%!
//产生随机颜色函数getRandColor
Color getRandColor(int fc,int bc){
Random r=new Random();
if(fc>255) fc=255;
if(bc>255) bc=255;
int red=fc+r.nextInt(bc-fc); //red
int green=fc+r.nextInt(bc-fc); //green
int blue=fc+r.nextInt(bc-fc); //blue
return new Color(red,green,blue);
}
%>
<%
//设置页面不缓存
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires",0);
//创建随机类
Random r=new Random();
//在内存中创建图像，宽度为width,高度为height
int width=60,height=20;
BufferedImage pic=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
//获取图形上下文环境
Graphics gc=pic.getGraphics();
//设定背景图形上下文填充
gc.setColor(getRandColor(200,250));
gc.fillRect(0,0,width,height);
//设定图形上下文环境字体
gc.setFont(new Font("Times New Roman",Font.PLAIN,18));
//随机产生200条干扰直线，使图像中的认证码不易被其他分析程序探测
gc.setColor(getRandColor(160,200));
for(int i=0;i<200;i++){
int x1=r.nextInt(width);
int y1=r.nextInt(height);
int x2=r.nextInt(15);
int y2=r.nextInt(15);
gc.drawLine(x1,y1,x1+x2,y1+y2);
}
//随机产生100个干扰点，使图像中的验证码不易被其他分析程序探测到
gc.setColor(getRandColor(120,240));
for(int i=0;i<100;i++)
{
int x=r.nextInt(width);
int y=r.nextInt(height);
gc.drawOval(x,y,0,0);
}
//随机产生4位数字的验证码
String RS="";
String rn="";
for(int i=0;i<4;i++){
//产生10以内的随机数字rn
rn=String.valueOf(r.nextInt(10));
RS+=rn;
//将认证码用drawString函数显示到图像里
gc.setColor(new
Color(20+r.nextInt(110),20+r.nextInt(110),20+r.nextInt(110)));
gc.drawString(rn,13*i+6,16);
}
//释放图形上下文环境
gc.dispose();
//将认证码RS存入SESSION中共享
session.setAttribute("random",RS);
//输出生成后的验证码图像到页面
ImageIO.write(pic,"jpeg",response.getOutputStream());
%>
效果图如下: