JSP Chinese Verification Code

<% @ Page pageencoding = "gb2312" contenttype = "image/JPEG" Import = "javax. imageIO. *, Java. util. *, Java. AWT. image. *, Java. AWT. * "%> <%! // Obtain and generate a random color here. Color getrandcolor (random, int ff, int CC) {If (FF> 255) FF = 255; If (CC> 255) cc = 255; int r = FF + random. nextint (CC-ff); int G = FF + random. nextint (CC-ff); int B = FF + random. nextint (CC-ff); return new color (R, G, B) ;}%><%// set no cache response on the JSP page. setheader ("Pragma", "No-Cache"); response. setheader ("cache-control", "No-Cache"); response. setdateheader ("Expires", 0); // set the length and width of the image to int width = 130; int Height = 30; // you can specify the number of randomly selected Chinese characters. In this example, there are too many texts, I will not list them one by one, just for example. String base = "\ u9752 \ u534a \ u706b \ u6cd5 \ signature \ u5efa \ signature \ u5531 \ signature \ u5973 \ signature \ u4ef6 \ u611f \ u51c6 \ u97f3 \ u7b54 \ u54e5 \ u9645 \ u65e7 \ u795e \ u5ea7 \ u7ae0 \ u538b \ u6162 \ u53d4 \ u80cc \ u7ec6 "; // set the number of alternative random Chinese characters int length = base. length (); // create the cached image bufferedimage image = new bufferedimage (width, height, bufferedimage. type_int_rgb); // obtain the image object graphics G = image. getgraphics (); // create the random function random = new random (); // set the image background color G. setcolor (getrandcolor (randdom, 188,235); G. fillrect (0, 0, width, height); // set the random alternative font type string [] fonttypes = {"\ u5b8b \ u4f53 ", "\ u65b0 \ u5b8b \ u4f53", "\ u9ed1 \ u4f53", "\ u6977 \ u4f53", "\ u96b6 \ u4e66"}; int fontpeslength = fonttypes. length; // Add noise on the image background to increase the difficulty of image analysis. setcolor (getrandcolor (randdom, 180,199); G. setfont (new font ("Times New Roman", Font. plain, 14); For (INT I = 0; I <4; I ++) {G. drawstring ("@ *", 0, 5 * (I + 2 ));} // obtain the randomly generated Verification Code (4 Chinese characters) // Save the Generated Chinese character string srand = ""; for (INT I = 0; I <4; I ++) {int start = random. nextint (length); string Rand = base. substring (start, start + 1); srand + = rand; // set the font color G on the image. setcolor (getrandcolor (random, 10,150); // set the font format G. setfont (new font (fonttypes [random. nextint (fonttypeslength)], Font. bold, 18 + random. nextint (6); // draw the Chinese character to the verification image G. drawstring (RAND, 24 * I + 10 + random. nextint (8), 24);} // Save the verification code to the session in s ession. setattribute ("RAND", srand); G. dispose (); // output the image to the ImageIO on the JSP page. write (image, "Jpeg", response. getoutputstream (); // close the stream out. clear (); out = pagecontext. pushbody (); %>