JSP verification code problem!

home page

& ltimg src="RandomCodeCtrl"/>。

web.xml

& ltservlet & gt

& ltservlet-name & gt； RandomCodeCtrl & lt/servlet-name & gt；

& ltservlet-class & gt； com . chain way . util . randomcodectrl & lt； /servlet-class & gt；

& lt Load & GT4 at startup & lt/load-on-startup >

& lt/servlet & gt；

& ltservlet mapping & gt

& ltservlet-name & gt； RandomCodeCtrl & lt/servlet-name & gt；

& lturl mode & gt/RandomCodeCtrl & lt； /URL-pattern & gt；

& lt/servlet-mapping & gt；

RandomCodeCtrl:

Package com.chainway.util;

Import java.io.ioexception;

Import javax.servlet.servletexception;

Import javax.servlet..chainway.util

Import java.awt.color;

Import java.awt.font;

Import java.awt.graphics;

Import java.awt.image.buffered image;

Import java.util.random;

Import javax.imageio.imageio;

Import javax.servlet.http.httpservletrequest;

Import javax.servlet.http.httpservletresponse;

Import javax.servlet.http.httpsession;

Public class RandomCode {

/**

* get a font at random

* @param Random random number

* @return Font returns the new font.

*/

Private synchronous font getsfont (random random) (

Returns the new font ("Fixedsys", font. CENTER_BASELINE， 18)；

}

/**

* Returns a random color.

* @param int fc random number

* @param int bc random number

* @param Random random number

* @return Color returns a new color.

*/

Sync color getRandColor(int fc, int bc, Random random){

if(fc & gt； 255)fc = 255；

if(BC & gt； 255)BC = 255；

int r = fc+random . nextint(BC-fc-6)；

int g = fc+random . nextint(BC-fc-4)；

int b = fc+random . nextint(BC-fc-8)；

Returns a new color (r, g, b);

}

/**

* generate random number pictures

*/

The public synchronization void getrandcode (HTTP Servlet Request, HttpServletResponse) throws an exception {

system . set property(" Java . awt . headless "，" true ")；

http session session = request . getsession()；

Int width=80, height = 26// Set the picture size.

BufferedImage image = new buffered image (width, height, buffered image. TYPE _ INT _ RGB)；

graphics g = image . get graphics()；

Random Random = new Random()；

g.fillRect(0，0，width，height)； //Set the border

G.setFont ("Times New Roman", font. ROMAN_BASELINE， 18)；

G. set color (get randcolor (111,133, random));

//Generate random lines

for(int I = 0； I< 1 1; i++){

int x = random . nextint(width)；

int y = random . nextint(height)；

int XL = random . nextint( 13)；

int yl = random . nextint( 15)；

g.drawLine(x，y，x+xl，y+yl)；

}

//Generate random points

g . set color(getRandColor( 130， 150，random))；

//Generate 5 random numbers

String sRand =

for(int I = 0； I<5; i++){

g . set font(gets font(random))；

g . set Color(new Color(random . nextint( 10 1)，random . nextint( 1 1 1)，random . nextint( 12 1)))；

//String rand = String . value of(getRandomString(random . nextint(36))；

string rand = string . value of(getRandomString(random . nextint( 10))；

sRand+= rand；

g.translate(random.nextInt(3)，random.nextInt(3))。

G. rope drawing (rand, 13*i,16);

}

session . remove attribute(" Rand ")；

session.setAttribute("Rand "，sRand)；

g . dispose()；

ImageIO.write(image，" JPEG "，response . get output stream())；

}

Common synchronization string getRandomString(int num){

string rand string = " 0 123456789 "；

//String rand String = " 0 123456789 abcdefghijklmnopqrstuvwxyz "；

Returns string.valueof (rand string.charat (num));

}

}

//landing judgment method

Get the verification code from the process and compare it.