Java generated image verification code used when logging in

 Packagecom.ws.frame.utils;ImportJava.awt.Color;ImportJava.awt.Font;ImportJava.awt.Graphics;ImportJava.awt.image.BufferedImage;Importjava.io.IOException;ImportJava.util.Random;ImportJavax.imageio.ImageIO;ImportJavax.servlet.http.HttpServletResponse;Importjavax.servlet.http.HttpSession;/*** Random Verification Code generation rules for page anti-violence hack *@authorYingfu*/ Public classCaptcha { Public Static FinalString Session_key = "CAPTCHA";//the name of the session property    Private Static Final intWIDTH = 80;//Picture Width    Private Static Final intHEIGHT = 26;//Picture Height    Private Static Final intLinesize = 8;//number of interference lines in pictures    Private Static Final intNumber = 4;//number of characters produced    Private Static Final intFONTSIZE = 18;//Picture Text Size    Private Static Final intR = 255; Private Static Final intG = 255; Private Static Final intB = 255; Private Static Final intDefault_font_style = Font.center_baseline;//Default Style    Private Static FinalString default_font_family = Font.sans_serif;//Default Font    /*** Random number generation pool*/    Private Static Final Char[] Charspool = {' 0 ', ' 1 ', ' 2 ', ' 3 ', ' 4 ', ' 5 ', ' 6 ',            ' 7 ', ' 8 ', ' 9 ', ' A ', ' B ', ' C ', ' d ', ' e ', ' f ', ' g ', ' h ', ' I ', ' J ',            ' K ', ' l ', ' m ', ' n ', ' o ', ' P ', ' Q ', ' R ', ' s ', ' t ', ' u ', ' V ', ' W ',            ' x ', ' y ', ' z ', ' A ', ' B ', ' C ', ' D ', ' E ', ' F ', ' G ', ' H ', ' I ', ' J ',            ' K ', ' L ', ' M ', ' N ', ' O ', ' P ', ' Q ', ' R ', ' S ', ' T ', ' U ', ' V ', ' W ',            ' X ', ' Y ', ' Z ' }; PrivateRandom random =NewRandom (); /*** Generate random characters *@returnstring*/    Private CharRandomcode () {intLength =charspool.length; intnum =random.nextint (length); returnCharspool[num]; }        /*** Set the style of random colors *@returnColor*/    PrivateColor Colorstyle () {intR =Random.nextint (R); intg =Random.nextint (G); intb =Random.nextint (B); return NewColor (R, G, b); }        /*** Set the basic style of the font *@returnFont*/    PrivateFont FontStyle () {//use for Linux serversSystem.setproperty ("Java.awt.headless", "true"); return NewFont (default_font_family, Default_font_style, FONTSIZE); }        /*** Set the color of the text *@return     */    PrivateColor Fontcolorstyle () {intr = Random.nextint (100); intg = Random.nextint (100); intb = Random.nextint (100); return NewColor (R, G, b); }        /*** Draw Random numbers *@paramG *@paramI *@returnChar*/    Private CharDrawrandomcode (Graphics G,inti) {G.setfont (FontStyle ());//G.setcolor (Colorstyle ());G.setcolor (Fontcolorstyle ()); CharRandomcode =Randomcode (); G.translate (Random.nextint (3), Random.nextint (3)); g.DrawString (String.valueof (randomcode),* I, 16); returnRandomcode; }        /*** Draw Interference lines *@paramg*/    Private voidDrawLine (Graphics g) {intx =Random.nextint (WIDTH); inty =Random.nextint (HEIGHT); intx2 = Random.nextint (WIDTH/2); inty2 = Random.nextint (height/2);    G.drawline (x, y, x2, y2); }        /*** Generate Verification code *@paramSession *@paramResponse*/     Public voidBuildcaptcha (HttpSession session, HttpServletResponse response) {BufferedImage image=Newbufferedimage (WIDTH, HEIGHT,BUFFEREDIMAGE.TYPE_INT_BGR); Graphics g=Image.getgraphics (); G.fillrect (0, 0, WIDTH, HEIGHT);        G.setfont (FontStyle ());        G.setcolor (Colorstyle ());  for(inti=0;i<linesize;i++) {drawLine (g); } StringBuilder Code=NewStringBuilder ();  for(intI=1; i<= number; i++) {code.append (Drawrandomcode (g, i));        } session.removeattribute (Session_key);        Session.setattribute (Session_key, code.tostring ());        G.dispose (); Try{imageio.write (image,"JPEG", Response.getoutputstream ()); } Catch(IOException e) {e.printstacktrace (); }    }}

The color of the font in the picture and the drawing line are randomly generated.

Java generated image verification code used when logging in