java生成验证码

JAVA代码：

AuthImage类:

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import java.io.IOException;    import javax.servlet.ServletException;  import javax.servlet.http.HttpServletRequest;  import javax.servlet.http.HttpServletResponse;  import javax.servlet.http.HttpSession;   /**   * <p><b>AuthImage Description:</b> (验证码)</p>   * <b>DATE:</b> 2016年6月2日 下午3:53:12   */ public class AuthImage extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {       static final long serialVersionUID = 1L;           public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {           response.setHeader( "Pragma" , "No-cache" );           response.setHeader( "Cache-Control" , "no-cache" );           response.setDateHeader( "Expires" , 0 );           response.setContentType( "image/jpeg" );                       //生成随机字串           String verifyCode = VerifyCodeUtils.generateVerifyCode( 4 );           //存入会话session           HttpSession session = request.getSession( true );           //删除以前的          session.removeAttribute( "verCode" );          session.setAttribute( "verCode" , verifyCode.toLowerCase());           //生成图片           int w = 100 , h = 30 ;           VerifyCodeUtils.outputImage(w, h, response.getOutputStream(), verifyCode);           }  }

VerifyCodeUtils类，生成图片流

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import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.RenderingHints; import java.awt.geom.AffineTransform; import java.awt.image.BufferedImage; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import java.util.Arrays; import java.util.Random;   import javax.imageio.ImageIO; /**   * <p><b>VerifyCodeUtils Description:</b> (验证码生成)</p>   * <b>DATE:</b> 2016年6月2日 下午3:53:34   */ public class VerifyCodeUtils{            //使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符      public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ" ;      private static Random random = new Random();          /**       * 使用系统默认字符源生成验证码       * @param verifySize    验证码长度       * @return       */      public static String generateVerifyCode( int verifySize){          return generateVerifyCode(verifySize, VERIFY_CODES);      }      /**       * 使用指定源生成验证码       * @param verifySize    验证码长度       * @param sources   验证码字符源       * @return       */      public static String generateVerifyCode( int verifySize, String sources){          if (sources == null || sources.length() == 0 ){              sources = VERIFY_CODES;          }          int codesLen = sources.length();          Random rand = new Random(System.currentTimeMillis());          StringBuilder verifyCode = new StringBuilder(verifySize);          for ( int i = 0 ; i < verifySize; i++){              verifyCode.append(sources.charAt(rand.nextInt(codesLen- 1 )));          }          return verifyCode.toString();      }            /**       * 生成随机验证码文件,并返回验证码值       * @param w       * @param h       * @param outputFile       * @param verifySize       * @return       * @throws IOException       */      public static String outputVerifyImage( int w, int h, File outputFile, int verifySize) throws IOException{          String verifyCode = generateVerifyCode(verifySize);          outputImage(w, h, outputFile, verifyCode);          return verifyCode;      }            /**       * 输出随机验证码图片流,并返回验证码值       * @param w       * @param h       * @param os       * @param verifySize       * @return       * @throws IOException       */      public static String outputVerifyImage( int w, int h, OutputStream os, int verifySize) throws IOException{          String verifyCode = generateVerifyCode(verifySize);          outputImage(w, h, os, verifyCode);          return verifyCode;      }            /**       * 生成指定验证码图像文件       * @param w       * @param h       * @param outputFile       * @param code       * @throws IOException       */      public static void outputImage( int w, int h, File outputFile, String code) throws IOException{          if (outputFile == null ){              return ;          }          File dir = outputFile.getParentFile();          if (!dir.exists()){              dir.mkdirs();          }          try {              outputFile.createNewFile();              FileOutputStream fos = new FileOutputStream(outputFile);              outputImage(w, h, fos, code);              fos.close();          } catch (IOException e){              throw e;          }      }            /**       * 输出指定验证码图片流       * @param w       * @param h       * @param os       * @param code       * @throws IOException       */      public static void outputImage( int w, int h, OutputStream os, String code) throws IOException{          int verifySize = code.length();          BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);          Random rand = new Random();          Graphics2D g2 = image.createGraphics();          g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);          Color[] colors = new Color[ 5 ];          Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN,                  Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,                  Color.PINK, Color.YELLOW };          float [] fractions = new float [colors.length];          for ( int i = 0 ; i < colors.length; i++){              colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];              fractions[i] = rand.nextFloat();          }          Arrays.sort(fractions);                    g2.setColor(Color.GRAY); // 设置边框色          g2.fillRect( 0 , 0 , w, h);                    Color c = getRandColor( 200 , 250 );          g2.setColor(c); // 设置背景色          g2.fillRect( 0 , 2 , w, h- 4 );                    //绘制干扰线          Random random = new Random();          g2.setColor(getRandColor( 160 , 200 )); // 设置线条的颜色          for ( int i = 0 ; i < 20 ; i++) {              int x = random.nextInt(w - 1 );              int y = random.nextInt(h - 1 );              int xl = random.nextInt( 6 ) + 1 ;              int yl = random.nextInt( 12 ) + 1 ;              g2.drawLine(x, y, x + xl + 40 , y + yl + 20 );          }                    // 添加噪点          float yawpRate = 0 .05f; // 噪声率          int area = ( int ) (yawpRate * w * h);          for ( int i = 0 ; i < area; i++) {              int x = random.nextInt(w);              int y = random.nextInt(h);              int rgb = getRandomIntColor();              image.setRGB(x, y, rgb);          }                    shear(g2, w, h, c); // 使图片扭曲            g2.setColor(getRandColor( 100 , 160 ));          int fontSize = h- 4 ;          Font font = new Font( "Algerian" , Font.ITALIC, fontSize);          g2.setFont(font);          char [] chars = code.toCharArray();          for ( int i = 0 ; i < verifySize; i++){              AffineTransform affine = new AffineTransform();              affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : - 1 ), (w / verifySize) * i + fontSize/ 2 , h/ 2 );              g2.setTransform(affine);              g2.drawChars(chars, i, 1 , ((w- 10 ) / verifySize) * i + 5 , h/ 2 + fontSize/ 2 - 10 );          }                    g2.dispose();          ImageIO.write(image, "jpg" , os);      }            private static Color getRandColor( int fc, int bc) {          if (fc > 255 )              fc = 255 ;          if (bc > 255 )              bc = 255 ;          int r = fc + random.nextInt(bc - fc);          int g = fc + random.nextInt(bc - fc);          int b = fc + random.nextInt(bc - fc);          return new Color(r, g, b);      }            private static int getRandomIntColor() {          int [] rgb = getRandomRgb();          int color = 0 ;          for ( int c : rgb) {              color = color << 8 ;              color = color | c;          }          return color;      }            private static int [] getRandomRgb() {          int [] rgb = new int [ 3 ];          for ( int i = 0 ; i < 3 ; i++) {              rgb[i] = random.nextInt( 255 );          }          return rgb;      }        private static void shear(Graphics g, int w1, int h1, Color color) {          shearX(g, w1, h1, color);          shearY(g, w1, h1, color);      }            private static void shearX(Graphics g, int w1, int h1, Color color) {            int period = random.nextInt( 2 );            boolean borderGap = true ;          int frames = 1 ;          int phase = random.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);              }          }        }        private static void shearY(Graphics g, int w1, int h1, Color color) {            int period = random.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);              }            }        }      public static void main(String[] args) throws IOException{          File dir = new File( "F:/verifies" );          int w = 200 , h = 80 ;          for ( int i = 0 ; i < 50 ; i++){              String verifyCode = generateVerifyCode( 4 );              File file = new File(dir, verifyCode + ".jpg" );              outputImage(w, h, file, verifyCode);          }      } }

　

web.xml写法

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<!-- 登录验证码 -->   <servlet>       <servlet-name>AuthImage</servlet-name>       <servlet- class >com.toft.widgets.login.AuthImage</servlet- class >       </servlet>       <servlet-mapping>       <servlet-name>AuthImage</servlet-name>       <url-pattern>/authImage</url-pattern>    </servlet-mapping>

JSP 页面写法，有刷新操作

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<!-- 验证码 --> <tr>     <td nowrap width= "437" ></td>      <td>          <img id= "img" src= "${ctx}/authImage" />          <a href= '#' onclick= "javascript:changeImg()" style= "color:white;" ><label style= "color:white;" >看不清？</label></a>      </td>   </tr>         <!-- 触发JS刷新-->   <script type= "text/javascript" >      function changeImg(){          var img = document.getElementById( "img" );           img.src = "${ctx}/authImage?date=" + new Date();;      } </script>