Java code generation image verification code implementation

Java code generation image verification code implementation

This section describes an example of using Java code to generate a random image verification code.

Can be directly configured as a Servlet and called directly on the page

Java code randomly generates an image Verification Code

Package com. rchm. util. images;

Import java. awt. Color;

Import java. awt. Font;

Import java. awt. Graphics2D;

Import java. awt. image. BufferedImage;

Import java. io. FileOutputStream;

Import java. io. IOException;

Import java. io. OutputStream;

Import java. util. Random;

Import javax. imageio. ImageIO;

/**

* Verification Code Generator

*/

Public class ValidateCode {

// The image width.

Private int width = 160;

// The Image Height.

Private int height = 40;

// Number of characters in the verification code

Private int codeCount = 5;

// Number of lines interfering with the verification code

Private int line COUNT = 150;

// Verification Code

Private static String code = null;

// Verification Code Image Buffer

Private BufferedImage buffImg = null;

Private 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 '};

Public ValidateCode (){

This. createCode ();

}

/**

*

* @ Param width: Image width

* @ Param height: Image height

*/

Public ValidateCode (int width, int height ){

This. width = width;

This. height = height;

This. createCode ();

}

/**

*

* @ Param width: Image width

* @ Param height: Image height

* @ Param codeCount: number of characters

* @ Param lineCount Number of interfering lines

*/

Public ValidateCode (int width, int height, int codeCount, int lineCount ){

This. width = width;

This. height = height;

This. codeCount = codeCount;

This. lineCount = lineCount;

This. createCode ();

}

Public void createCode (){

Int x = 0, fontHeight = 0, codeY = 0;

Int red = 0, green = 0, blue = 0;

X = width/(codeCount + 2); // The width of each character

FontHeight = height-2; // font height

CodeY = height-4;

// Image buffer

BuffImg = new BufferedImage (width, height, BufferedImage. TYPE_INT_RGB );

Graphics2D g = buffImg. createGraphics ();

// Generate a random number

Random random = new Random ();

// Fill the image in white

G. setColor (Color. WHITE );

G. fillRect (0, 0, width, height );

// Create a font

ImgFontByte imgFont = new ImgFontByte ();

Font font = imgFont. getFont (fontHeight );

G. setFont (font );

For (int I = 0; I

Int xs = random. nextInt (width );

Int ys = random. nextInt (height );

Int xe = xs + random. nextInt (width/8 );

Int ye = ys + random. nextInt (height/8 );

Red = random. nextInt (255 );

Green = random. nextInt (255 );

Blue = random. nextInt (255 );

G. setColor (new Color (red, green, blue ));

G. drawLine (xs, ys, xe, ye );

}

// RandomCode records the randomly generated Verification Code

StringBuffer randomCode = new StringBuffer ();

// Generate a random codeCount verification code.

For (int I = 0; I

String strRand = String. valueOf (codeSequence [random. nextInt (codeSequence. length)]);

// Generate random color values so that the color values of each character are different.

Red = random. nextInt (255 );

Green = random. nextInt (255 );

Blue = random. nextInt (255 );

G. setColor (new Color (red, green, blue ));

G. drawString (strRand, (I + 1) * x, codeY );

// Combine the four random numbers.

RandomCode. append (strRand );

}

// Save the four-digit verification code to the Session.

Code = randomCode. toString ();

}

Public void write (String path) throws IOException {

OutputStream sos = new FileOutputStream (path );

This. write (sos );

}

Public void write (OutputStream sos) throws IOException {

ImageIO. write (buffImg, "png", sos );

Sos. close ();

}

Public BufferedImage getBuffImg (){

Return buffImg;

}

Public static String getCode (){

Return code;

}

}

Use this class in servlet:

Package com. rchm. util. images;

Import java. io. IOException;

Import javax. servlet. ServletException;

Import javax. servlet. http. HttpServlet;

Import javax. servlet. http. HttpServletRequest;

Import javax. servlet. http. HttpServletResponse;

Import javax. servlet. http. HttpSession;

Public class ValidateCodeServlet extends HttpServlet {

Private static final long serialVersionUID = 1L;

Protected void doGet (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

Response. setContentType ("image/jpeg ");

Response. setHeader ("Pragma", "no-cache ");

Response. setHeader ("Cache-Control", "no-cache ");

Response. setDateHeader ("Expires", 0 );

ValidateCode vCode = new ValidateCode (4,100, 30 );

HttpSession session = request. getSession ();

Session. removeAttribute ("validateCode ");

VCode. write (response. getOutputStream ());

Session. setAttribute ("validateCode", vCode. getCode ());

VCode. write (response. getOutputStream ());

}

}

Configure the Servlet access path in web. xml:

ValidateCodeServlet

Class> com. rchm. util. images. ValidateCodeServletclass>

ValidateCodeServlet