image.jsp

java + sqlserver2000编写的一个网上购书系统,实现了一些基本的功能,但对于初学者来说这个系统已经足以起到帮助作用

<%@ 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 width=60, height=20;
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));

//???
//g.setColor(new Color());
//g.drawRect(0,0,width-1,height-1);


// ????155???????????????????????
g.setColor(getRandColor(160,200));
for (int i=0;i<155;i++)
{
 int x = random.nextInt(width);
 int y = random.nextInt(height);
        int xl = random.nextInt(12);
        int yl = random.nextInt(12);
 g.drawLine(x,y,x+xl,y+yl);
}

// ?????????(4???)
String sRand="";
for (int i=0;i<4;i++){
    String rand=String.valueOf(random.nextInt(10));
    sRand+=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
session.setAttribute("rand",sRand);


// ????
g.dispose();

// ???????
ImageIO.write(image, "JPEG", response.getOutputStream());


%>