JSP servlet Verification Code

1   Package Net. cmono. javaweb. C3;
 2  
 3   Import Java. AWT. color;
 4   Import Java. AWT. Font;
 5   Import Java. AWT. graphics2d;
 6   Import Java. AWT. image. bufferedimage;
 7  Import Java. Io. ioexception;
 8   Import Java. Io. printwriter;
 9   Import Java. util. Random;
 10  
 11   Import Javax. servlet. servletexception;
 12   Import Javax. servlet. servletoutputstream;
 13   Import Javax. servlet. http. httpservlet;
 14   Import Javax. servlet. http. httpservletrequest;
 15   Import Javax. servlet. http. httpservletresponse;
 16  
 17   Import Com. Sun. CORBA. se. impl. ior. newobjectkeytemplatebase;
 18   Import Com.sun.image.codec.jpeg. Unzip codec;
 19   Import Com.sun.image.codec.jpeg. Specify imageencoder;
 20  
 21   Public   Class Identityservlet Extends Httpservlet {
 22  
 23       /**  
  24   * Constructor of the object.
  25   */ 
26       Public Identityservlet (){
 27           Super ();
 28 }
 29  
 30       /**  
  31   * Destruction of the servlet. <br>
  32   */ 
 33      Public   Void Destroy (){
 34           Super . Destroy (); //  Just puts "Destroy" string in log
  35   //  Put your code here  
  36 }
 37  
 38       /**  
 39   * The doget method of the servlet. <br>
  40   *
  41   * This method is called when a form has its tag Value Method equals to get.
  42   *
  43   *  @ Param  Request the request send by the client to the server
  44   * @ Param  Response the response send by the server to the client
  45   *  @ Throws  Servletexception if an error occurred
  46   *  @ Throws  Ioexception if an error occurred
  47   */ 
 48       Public   Void Doget (httpservletrequest request, httpservletresponse response)
 49               Throws Servletexception, ioexception {
 50  
 51 Response. setcontenttype ("image/JPEG ");
 52          
 53 String randomstring = getrandomstring ();
 54 Request. getsession ( True ). Setattribute ("randomstring", randomstring );
 55          
56           Int Length = 100;
 57           Int Height = 30;
 58          
 59 Color color = getrandomcolor ();
 60 Color reverse = getreversecolor (color );
 61          
 62 Bufferedimage Bi = New Bufferedimage (width, height, bufferedimage. type_int_rgb );
63          
 64 Graphics2d G = Bi. creategraphics ();
 65 G. setfont ( New Font (font. sans_serif, Font. Bold, 16 ));
 66 G. setcolor (color );
 67 G. fillrect (0, 0, width, height );
 68 G. setcolor (reverse );
 69 G. drawstring (randomstring, 18, 20 );
 70          
71           For ( Int I = 0, n = random. nextint (100); I <n; I ++)
 72 {
 73 G. drawrect (random. nextint (width), random. nextint (height), 1, 1 );
 74 }
 75          
 76 Servletoutputstream out = response. getoutputstream ();
 77          
 78 Required imageencoder encoder = required codec. createjpegencoder (out );
 79          
 80 Encoder. encode (BI );
 81          
 82 Out. Flush ();
 83          
 84 }
 85  
 86       /**  
  87  * The dopost method of the servlet. <br>
  88   *
  89   * This method is called when a form has its tag Value Method equals to post.
  90   *
  91   *  @ Param  Request the request send by the client to the server
  92   *  @ Param Response the response send by the server to the client
  93   *  @ Throws  Servletexception if an error occurred
  94   *  @ Throws  Ioexception if an error occurred
  95   */ 
 96       Public   Void Dopost (httpservletrequest request, httpservletresponse response)
 97               Throws Servletexception, ioexception {
 98          
 99 }
 100  
 101       /**  
  102   * Initialization of the servlet. <br>
  103   *
 104   *  @ Throws  Servletexception if an error occurs
  105   */ 
 106       Public   Void Init () Throws Servletexception {
 107           //  Put your code here  
  108 }
 109  
 110       Public   Static   Final   Char [] Chars = {'2', '3', '4', '5', '6', '7', '8', '9 ', 'A', 'B', 'C', 'D', 'E', 'E', 'F', 'G', 'h', 'J', 'k ',
 111 'L', 'M', 'n', 'P', 'Q', 'R', 's', 't', 'U', 'V ', 'w', 'x', 'y', 'z '};
 112      
 113       Public   Static Random random = New Random ();
 114      
 115       Public   Static String getrandomstring ()
 116 {
 117 Stringbuffer buffer = New Stringbuffer ();
 118           For ( Int I = 0; I <6; I ++)
 119 {
 120 Buffer. append (chars [random. nextint (chars. Length)]);
 121 }
 122          
 123           Return Buffer. tostring ();
 124 }
 125      
 126       Public   Static Color getrandomcolor ()
 127 {
 128          Return   New Color (random. nextint (255), random. nextint (255), random. nextint (255 ));
 129 }
 130      
 131       Public   Static Color getreversecolor (color C)
 132 {
 133           Return   New Color (255-C. getred (), 255-C. getgreen (), 255-c.getblue ());
134 }
 135      
 136 }

 

 1   <  Script  Type  = "Text/JavaScript"  >  
  2   Function  Reloadimage ()
  3  {
  4   Document. getelementbyid (  '  BTN  '  ). Disabled  =   True  ;
  5   Document. getelementbyid ( '  Identity  '  ). SRC  =  '  Servlet/indentityservlet? TS  '   +   New  Date (). gettime ();
  6  }
  7   </  Script  > 
 8  
 9   <  IMG  SRC  = "Servlet/identityservlet"  ID  = "Identity"  Onload  = "BTN. Disabled = false ;"  
 10   
  11   <Input type  = "Button"  Value  = "Change image"  Onclick  = "Reloadimage ()"  ID  = "BTN"   />