Vcode. jsp Verification Code

If you want to reference it as an image, OK

 

 

<% @ Page contenttype = "image/JPEG" %> <br/> <% @ page import = "Java. AWT. * "%> <br/> <% @ page import =" Java. AWT. image. * "%> <br/> <% @ page import =" Java. util. * "%> <br/> <% @ page import =" javax. imageIO. * "%> <br/> <% @ page import =" Java. io. outputstream "%> </P> <p> <%! <Br/> color getrandcolor (int fc, int BC) {// obtain a random color from a given range <br/> random = new random (); <br/> If (FC> 255) fc = 255; <br/> If (BC> 255) BC = 255; <br/> int r = FC + random. nextint (BC-Fc); <br/> int G = FC + random. nextint (BC-Fc); <br/> int B = FC + random. nextint (BC-Fc); <br/> return new color (R, G, B ); <br/>}< br/>%> <br/> <% <br/> // set the page to not cache <br/> response. setheader ("Pragma", "No no-Cache"); <br/> response. setheader ("cache-control", "No-Cache"); <br/> response. setdateheader ("expires", 0); </P> <p> // create an image in the memory <br/> int width = 60, Height = 20; <br/> bufferedimage image = new bufferedimage (width, height, bufferedimage. type_int_rgb); </P> <p> // obtain the image context <br/> graphics G = image. getgraphics (); </P> <p> // generate a random class <br/> random = new random (); </P> <p> // set the background color <br/> G. setcolor (getrandcolor (200,250); <br/> G. fillrect (0, 0, width, height); </P> <p> // set the font <br/> G. setfont (new font ("Times New Roman", Font. plain, 18); </P> <p> // generates 155 random interference lines, make the authentication code in the image difficult to be detected by other <SPAN class = 'wp _ keywordlink '> Programs </span> <br/> G. setcolor (getrandcolor (160,200); <br/> for (INT I = 0; I <155; I ++) <br/>{< br/> int x = random. nextint (width); <br/> int y = random. nextint (height); <br/> int XL = random. nextint (12); <br/> int yl = random. nextint (12); <br/> G. drawline (X, Y, x + XL, Y + yl); <br/>}</P> <p> // obtain the random ID code (4 digits) <br/> string srand = ""; <br/> for (INT I = 0; I <4; I ++) {<br/> string Rand = string. valueof (random. nextint (10); <br/> srand + = rand; <br/> // display the authentication code in the image <br/> G. setcolor (new color (20 + random. nextint (110), 20 + random. nextint (110), 20 + random. nextint (110); <br/> // The color from the call function is the same, probably because the seed is too close, so it can only be directly generated <br/> G. drawstring (RAND, 13 * I + 6, 16); <br/>}</P> <p> // Save the authentication code to the session <br/> session. setattribute ("RAND", srand); </P> <p> // draw an image <br/> G. dispose (); </P> <p> outputstream OS = response. getoutputstream (); <br/> // output the image to the page <br/> ImageIO. write (image, "Jpeg", OS); </P> <p> // clear the out object of JSP to avoid the out object in servelet and the response above. getoutputstream conflict <br/> out. clear (); <br/> out = pag. pushbody (); </P> <p >%> <br/>