Java programming verification code sent to mobile phone

& lt% @ page content type = " image/JPEG " import = " Java . awt . *，java.awt.image.*，java.util.*，javax.imageio. * " % & gt

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Color get randcolor (int fc, int BC){// Get random colors in a given range.

Random Random = new Random()；

if(fc & gt； 255)fc = 255；

if(BC & gt； 255)BC = 255；

int r = fc+random . nextint(BC-fc)；

int g = fc+random . nextint(BC-fc)；

int b = fc+random . nextint(BC-fc)；

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

}

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//Set the page not to be cached.

Response.setHeader("Pragma ","no cache ");

response . set header(" Cache-Control "，" no-Cache ")；

response . setdate header(" Expires "，0)；

//Create an image in memory

int width=60，height = 20

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

//Get the graphic context

graphics g = image . get graphics()；

//Generate a random class

Random Random = new Random()；

//Set the background color

g.setColor(getRandColor(200，250))；

g.fillRect(0，0，width，height)；

//Set the font

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

//Draw a border

//g . set Color(new Color())；

//g.drawRect(0，0，width- 1，height- 1)；

// 155 interference lines are randomly generated, which makes the authentication code in the image difficult to be detected by other programs.

g . set color(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)；

}

//Take the randomly generated authentication code (4 digits)

//String rand = request . getparameter(" rand ")；

//rand = rand.substring(0，rand.indexOf(" . "));

String sRand =

for(int I = 0； I<4; i++){

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

sRand+= rand；

//Display the verification code in the image.

g . set Color(new Color(20+random . nextint( 1 10)，20+random . nextint( 1 10)，20+random . nextint( 1 10)))； //The calling functions are all the same color, probably because the seeds are too close, so they can only be generated directly.

G. rope drawing (rand, 13*i+6,16);

}

//Store the authentication code in the session.

session.setAttribute("ccode "，sRand)；

//Image takes effect

g . dispose()；

//Output the image to the page

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

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