java输出扭曲验证码

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.font.FontRenderContext;
import java.awt.font.TextLayout;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.text.AttributedString;
import java.util.Random;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class SimpleCaptcha extends HttpServlet {
private Random generator = new Random();
private final static String SIMPLE_CAPCHA_SESSION_KEY = " SIMPLE_CAPCHA_SESSION_KEY " ;

private static char [] captchars = new char [] { ' a ' , ' b ' , ' c ' , ' d ' , ' e ' ,
    ' 2 ' , ' 3 ' , ' 4 ' , ' 5 ' , ' 6 ' , ' 7 ' , ' 8 ' , ' g ' , ' f ' , ' y ' , ' n ' , ' m ' , ' n ' ,
    ' p ' , ' w ' , ' x ' };

/**
  * 产生随机字体
  *
  * @return
   */
private Font getFont() {
  Random random = new Random();
  Font font[] = new Font[ 5 ];
  font[ 0 ] = new Font( " Ravie " , Font.PLAIN, 45 );
  font[ 1 ] = new Font( " Antique Olive Compact " , Font.PLAIN, 45 );
  font[ 2 ] = new Font( " Forte " , Font.PLAIN, 45 );
  font[ 3 ] = new Font( " Wide Latin " , Font.PLAIN, 40 );
  font[ 4 ] = new Font( " Gill Sans Ultra Bold " , Font.PLAIN, 45 );
   return font[random.nextInt( 5 )];
}

/**
  * 随机产生定义的颜色
  *
  * @return
   */
private Color getRandColor() {
  Random random = new Random();
  Color color[] = new Color[ 10 ];
  color[ 0 ] = new Color( 32 , 158 , 25 );
  color[ 1 ] = new Color( 218 , 42 , 19 );
  color[ 2 ] = new Color( 31 , 75 , 208 );
   return color[random.nextInt( 3 )];
}

/**
  * @see javax.servlet.http.HttpServlet#void
  *      (javax.servlet.http.HttpServletRequest,
  *      javax.servlet.http.HttpServletResponse)
   */
public void doGet(HttpServletRequest req, HttpServletResponse resp)
    throws ServletException, IOException {

   int ImageWidth = 200 ;
   int ImageHeight = 100 ;

   int car = captchars.length - 1 ;
   /**
   * 产生随机字符串
    */
  String test = "" ;
   for ( int i = 0 ; i < 4 ; i ++ ) {
   test += captchars[generator.nextInt(car) + 1 ];
  }
   /**
   * 放放Session
    */
  req.getSession().setAttribute(SimpleCaptcha.SIMPLE_CAPCHA_SESSION_KEY,
    test);
   /**
   * 得到输出流
    */
  JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(resp
    .getOutputStream());

  BufferedImage bi = new BufferedImage(ImageWidth + 10 , ImageHeight,
    BufferedImage.TYPE_BYTE_INDEXED);

  Graphics2D graphics = bi.createGraphics();

   /**
   * 设置背景色
    */
  graphics.setColor(Color.white);

  graphics.fillRect( 0 , 0 , bi.getWidth(), bi.getHeight());

  graphics.setColor(Color.black);
  AttributedString attstr = new AttributedString(test);

  TextLayout textTl = new TextLayout(test, new Font( " Courier " , Font.BOLD,
     70 ), new FontRenderContext( null , true , false ));
  AffineTransform textAt = graphics.getTransform();
  graphics.setFont( new Font( " Courier " , Font.BOLD, 70 ));
  graphics.setColor( this .getRandColor());
  graphics.drawString(test, 10 , 70 );
//   textTl.draw(graphics, 4, 60);
   int w = bi.getWidth();
   int h = bi.getHeight();
  shear(graphics, w, h, Color.white);
   // this.drawThickLine(graphics, 0, generator.nextInt(ImageHeight) + 1,
   // ImageWidth, generator.nextInt(ImageHeight) + 1, 4, Color.BLACK);

  resp.setContentType( " image/jpg " );

  encoder.encode(bi);

}

private void shear(Graphics g, int w1, int h1, Color color) {

  shearX(g, w1, h1, color);
  shearY(g, w1, h1, color);
}

public void shearX(Graphics g, int w1, int h1, Color color) {

   int period = generator.nextInt( 2 );

   boolean borderGap = true ;
   int frames = 1 ;
   int phase = generator.nextInt( 2 );

   for ( int i = 0 ; i < h1; i ++ ) {
    double d = ( double ) (period >> 1 )
      * Math.sin(( double ) i / ( double ) period
        + ( 6.2831853071795862D * ( double ) phase)
        / ( double ) frames);
   g.copyArea( 0 , i, w1, 1 , ( int ) d, 0 );
    if (borderGap) {
    g.setColor(color);
    g.drawLine(( int ) d, i, 0 , i);
    g.drawLine(( int ) d + w1, i, w1, i);
   }
  }

}

public void shearY(Graphics g, int w1, int h1, Color color) {

   int period = generator.nextInt( 40 ) + 10 ; // 50;

   boolean borderGap = true ;
   int frames = 20 ;
   int phase = 7 ;
   for ( int i = 0 ; i < w1; i ++ ) {
    double d = ( double ) (period >> 1 )
      * Math.sin(( double ) i / ( double ) period
        + ( 6.2831853071795862D * ( double ) phase)
        / ( double ) frames);
   g.copyArea(i, 0 , 1 , h1, 0 , ( int ) d);
    if (borderGap) {
    g.setColor(color);
    g.drawLine(i, ( int ) d, i, 0 );
    g.drawLine(i, ( int ) d + h1, i, h1);
   }

  }

}

private void drawThickLine(Graphics g, int x1, int y1, int x2, int y2,
    int thickness, Color c) {

   // The thick line is in fact a filled polygon
  g.setColor(c);
   int dX = x2 - x1;
   int dY = y2 - y1;
   // line length
   double lineLength = Math.sqrt(dX * dX + dY * dY);

   double scale = ( double ) (thickness) / ( 2 * lineLength);

   // The x and y increments from an endpoint needed to create a
   // rectangle

   double ddx = - scale * ( double ) dY;
   double ddy = scale * ( double ) dX;
  ddx += (ddx > 0 ) ? 0.5 : - 0.5 ;
  ddy += (ddy > 0 ) ? 0.5 : - 0.5 ;
   int dx = ( int ) ddx;
   int dy = ( int ) ddy;

   // Now we can compute the corner points

   int xPoints[] = new int [ 4 ];
   int yPoints[] = new int [ 4 ];

  xPoints[ 0 ] = x1 + dx;
  yPoints[ 0 ] = y1 + dy;
  xPoints[ 1 ] = x1 - dx;
  yPoints[ 1 ] = y1 - dy;
  xPoints[ 2 ] = x2 - dx;
  yPoints[ 2 ] = y2 - dy;
  xPoints[ 3 ] = x2 + dx;
  yPoints[ 3 ] = y2 + dy;

  g.fillPolygon(xPoints, yPoints, 4 );
}

}

java输出扭曲验证码

你可能感兴趣的:(java输出扭曲验证码)