利用Java编写一个验证码生成功能

package com.SM_test.utils; 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;  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();        public static String generateVerifyCode(int verifySize){      return generateVerifyCode(verifySize, VERIFY_CODES);    }        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();    }        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;    }        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;    }        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;      }    }        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, 255);      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(50, 255));// 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() &#63; 1 : -1), (w / verifySize) * i + fontSize/2, h/2);        g2.setTransform(affine);       g2.setColor(getRandColor(100, 160));       g2.drawChars(chars, i, 1, ((w-10) / verifySize) * i + 5, h-(h - (int)(fontSize*0.75))/2);      }      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 h2, Color color) {      shearX(g, w1, h2, color);      shearY(g, w1, h2, color);    }    private static void shearX(Graphics g, int w1, int h2, Color color) {      int period = random.nextInt(2);      boolean borderGap = true;      int frames = 1;      int phase = random.nextInt(2);      for (int i = 0; i < h2; 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 h2, 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, h2, 0, (int) d);        if (borderGap) {          g.setColor(color);          g.drawLine(i, (int) d, i, 0);          g.drawLine(i, (int) d + h2, i, h2);        }      }    }    public static void main(String[] args) throws IOException{      File dir = new File("e:/abc");      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);      }    }  }