Java Generate CAPTCHA Code

Generate Base64 format Picture Verification code

1  /**2 * Generate Verification code3 * Transform the way to generate verification code, the picture Base64 form to the foreground, rather than directly pass the verification code to the front desk4      * @return5      * @throwsIOException6      */7      Public voidImagecode ()throwsIOException {8HttpServletResponse resp =commandcontext.getresponse ();9HttpServletRequest req =commandcontext.getrequest ();TenString method=Req.getmethod (); One         if("Options". Equals (method)) { A             return ; -         } -Map map=NewHashMap (); the  -         //Create an image in memory -         intwidth = +, height = 38; -BufferedImage image =Newbufferedimage (width, height, + Bufferedimage.type_int_rgb); -         //Get the graphics context +Graphics g =image.getgraphics (); A         //Generating Random classes atRandom random =NewRandom (); -         //Set Background color -G.setcolor (Getrandcolor (230, 255)); -G.fillrect (0, 0, 100, 40); -         //Set Font -G.setfont (NewFont ("Arial", Font.center_baseline | Font.Italic, 20)); in         //generates 0 lines of interference, -G.drawline (0, 0, 0, 0); to  +         //Store Verification Code -StringBuffer SRand =NewStringBuffer (); the          for(inti = 0; i < charcount; i++) { *String Singlecode =string.valueof (Codesequence[random.nextint (codesequence.length)); $ srand.append (singlecode);Panax Notoginseng             //Display the authentication code to the image -G.setcolor (Getrandcolor (100, 150));//The call function comes out with the same color, possibly because the seed is too close, so it can only be generated directly theg.DrawString (Singlecode, + * i + 5, 25); +         } A          for(inti=0;i< (Random.nextint (5) +5); i++){ theG.setcolor (NewColor (Random.nextint (255) +1,random.nextint (255) +1,random.nextint (255) +1)); +G.drawline (Random.nextint), Random.nextint (+), Random.nextint (+), Random.nextint (40)); -G.drawline (Random.nextint), Random.nextint (+), Random.nextint (+), Random.nextint (40)); $         } $  -HttpSession session =req.getsession (); -         //Get ClientID theString clientid=Systemutil.getclientid (req); -         if(Stringutils.isempty (clientId)) {Wuyi             //Generate ClientID theString Useragent=req.getheader ("User-agent"); -String sessionid=Session.getid (); WuString cip=Ippolicy.getclientip (req); -Clientid=Codeutil.genclientid (sessionid,cip,useragent); About         } $Map.put ("ClientId", clientId); -         if(isvalidatecodecasesensitive) { -Session.setattribute ("Randomcode", srand.tostring ()); - Systemutil.push2cache (ClientId, srand.tostring ()); A}Else { +Session.setattribute ("Randomcode", Srand.tostring (). toLowerCase ()); the Systemutil.push2cache (ClientId, Srand.tostring (). toLowerCase ()); -         } $         //Image Effective the g.dispose (); the         Try{ the  theBytearrayoutputstream OutputStream =NewBytearrayoutputstream (); -Imageio.write (image, "JPG", outputstream); inBase64encoder encoder =NewBase64encoder (); theString base64img =Encoder.encode (Outputstream.tobytearray ()); theBase64img= "Data:image/jpg;base64," +base64img.replaceall ("\ n", ""). ReplaceAll ("\ R", "");//delete \ r \ n; AboutMap.put ("Vercode", base64img); theObject jsonobj =Jsonserializer.tojson (map); the             byte[] json = jsonobj.tostring (). GetBytes ("UTF-8"); theResp.setcontenttype ("Text/plain;chartset=utf-8"); +Resp.setheader ("Cache-control", "No-cache"); -Resp.setheader ("Expires", "0"); theResp.setintheader ("Content-length", json.length);BayiServletoutputstream Responseoutputstream =Resp.getoutputstream (); the Responseoutputstream.write (JSON); the             //The following closes the input stream!  - Responseoutputstream.flush (); - responseoutputstream.close (); the             //Get page Key value the             return ; the}Catch(IOException e) { theLogger.error ("Production Verification Code Error", e); -             Throw NewSystemException ("Production Verification Code Error", e); the         } the     } the 94  the     /** the * get random colors for a given range the      *98      * @paramFC About      * @paramBC -      * @return101      */102Color Getrandcolor (intFcintBC) {103Random random =NewRandom ();104         if(FC > 255) theFC = 255;106         if(BC > 255)107BC = 255;108         intr = FC + random.nextint (BC-FC);109         intg = FC + random.nextint (BC-FC); the         intB = fc + random.nextint (BC-FC);111         return NewColor (R, G, b); the}

Java Generate CAPTCHA Code