Java Verification Code

 Public classVerifycodecontroller {Private intwidth = -;//define the width of the picture    Private intHeight = -;//defines the height of a picture    Private intCodecount =4;//define the number of verification codes displayed on the image    Private intxx = the; Private intFontheight = -; Private intCodey = -; Char[] Codesequence = {'A','B','C','D','E','F','G','H','I','J',             'K','L','M','N','P','Q','R','S','T','U','V','W',             'X','Y','Z','1','2','3','4','5','6','7','8','9' }; @RequestMapping ("/getverifycode")     Public voidGetverifycode (httpservletrequest req, HttpServletResponse resp) throws IOException {//defining the image bufferBufferedImage buffimg =Newbufferedimage (width, height, bufferedimage.type_int_rgb);//graphics2d gd = Buffimg.creategraphics (); //graphics2d gd = (graphics2d) buffimg.getgraphics (); Graphics GD =Buffimg.getgraphics (); //Create a random number generator classRandom random =NewRandom (); //fill the image with whiteGd.setcolor (Color.White); Gd.fillrect (0,0, width, height); //To create a font, the size of the font should depend on the height of the image. Font font =NewFont ("Fixedsys", Font.Bold, fontheight); //sets the font. Gd.setfont (font); //draw a border. Gd.setcolor (Color.Black); Gd.drawrect (0,0, Width-1, Height-1); //randomly generates 40 lines of interference so that the authentication code in the image is not easily detected by other programs. Gd.setcolor (Color.Black);  for(inti =0; I < +; i++) {                 intx =random.nextint (width); inty =random.nextint (height); intXL = Random.nextint ( A); intYL = Random.nextint ( A); Gd.drawline (x, y, x+ XL, Y +yl); }                  //The Randomcode is used to save randomly generated verification codes so that users can log in and authenticate. StringBuffer Randomcode =NewStringBuffer (); intRed =0, green =0, blue =0; //random generation of Codecount number verification code.              for(inti =0; i < Codecount; i++) {                 //get a randomly generated captcha number. String Code =string.valueof (Codesequence[random.nextint (codesequence.length)); //generates a random color component to construct a color value so that the output will have a different color value for each digit. Red = Random.nextint (255); Green= Random.nextint (255); Blue= Random.nextint (255); //draws the verification code into the image with a randomly generated color. Gd.setcolor (NewColor (red, green, blue)); Gd.drawstring (Code, (I+1) *xx, Codey); //The resulting four random numbers are grouped together. randomcode.append (code); }             //Save the four-digit verification code to the session. HttpSession session =req.getsession (); System. out. Print (Randomcode); Session.setattribute ("Verifycode", randomcode.tostring ()); //suppresses image caching. Resp.setheader ("Pragma","No-cache"); Resp.setheader ("Cache-control","No-cache"); Resp.setdateheader ("Expires",0); Resp.setcontenttype ("Image/jpeg"); //output the image to the servlet output stream. Servletoutputstream SOS =Resp.getoutputstream (); Imageio.write (buffimg,"JPEG", SOS);             Sos.close (); }

Java Verification Code