JSP generation Verification Code source program

Js| Program | Verification Code <%@ page contenttype= "Image/jpeg import=" java.awt.*,
Java.awt.image.*,java.util.*,javax.imageio.* "%>
<%
Create an image in memory
int width=60, height=20;
BufferedImage image = new BufferedImage (width, height,
BUFFEREDIMAGE.TYPE_INT_RGB);

Get Graphics context
Graphics g = image.getgraphics ();

Set Background color
G.setcolor (New Color (0xDCDCDC));
G.fillrect (0, 0, width, height);

Draw a border
G.setcolor (Color.Black);
G.drawrect (0,0,width-1,height-1);

Take a randomly generated authentication code (4 digits)
String rand = Request.getparameter ("Rand");
Rand = rand.substring (0,rand.indexof ("."));
Switch (Rand.length ())
{
Case 1:rand = "+rand"; Break
Case 2:rand = "+rand"; Break
Case 3:rand = "0" +rand; Break
Default:rand = rand.substring (0,4); Break
}

Save authentication Code in session
Session.setattribute ("Rand", Rand);

Display the authentication code in the image
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);

Randomly generated 88 interference points, so that the image of the authentication code is not easily detected by other programs
Random Random = new Random ();
for (int i=0;i<20;i++)
{
int x = random.nextint (width);
int y = random.nextint (height);
G.drawoval (x,y,0,0);
}

Image entry into force
G.dispose ();

Output image to Page
Imageio.write (Image, "JPEG", Response.getoutputstream ());
%>