image.jsp

本代码实现用户登录的功能

<%@ page contentType="image/jpeg" 
import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*"%> 
<%!
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);
}
 %>
 <%
 response.setHeader("Pragma","No-cache");
 response.setHeader("Cache-Control","No-cache");
 response.setDateHeader("Expires",0);
 
 int i_width=60;
 int i_heigth=20;
 BufferedImage image=new BufferedImage(i_width,i_heigth,BufferedImage.TYPE_INT_RGB);
 
 Graphics g=image.getGraphics();
 Random random=new Random();
 
 g.setColor(getRandColor(200,500));
 g.fillRect(0,0,i_width,i_heigth);
 
 g.setFont(new Font("Times new Roman",Font.PLAIN,18));
 
 g.setColor(getRandColor(160,200));
 for(int i=0;i<155;i++)
 {
 int i_x=random.nextInt(i_width);
 int i_y=random.nextInt(i_heigth);
 int i_x1=random.nextInt(12);
 int i_y1=random.nextInt(12);
 g.drawLine(i_x,i_y,i_x+i_x1,i_y+i_y1);
 }
 
 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);
 }
 
 session.setAttribute("rand",s_Rand);
 
 g.dispose();
 
 ImageIO.write(image,"JPEG",response.getOutputStream());

  %>