java生成验证码图片的方法

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.lang.RandomStringUtils;
import org.apache.commons.lang.StringUtils;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.util.Random;



public class RandomVerifyCode {

  private static final String RANDOM_NUM = "23456789";
  private static final String RANDOM_LETTER = "ABCDEFGHJKMNPQRSTUVWXYZ";
  private static final String RANDOM_LETTER_SMALL = "abcdefghjkmnpqrstuvwxyz";
  private static final String RANDOM_STRING = RANDOM_NUM + RANDOM_LETTER + RANDOM_LETTER_SMALL;

  private int width = 95;// 图片宽
  private int height = 25;// 图片高
  private int lineSize = 40;// 干扰线数量
  private int stringNum = 4;// 随机产生字符数量

  private Random random = new Random();


  /**
   * 获得字体
   */
  private Font getFont() {
    return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
  }

  /**
   * 获得颜色
   */
  private Color getRandColor(int fc, int bc) {
    if (fc > 255)
      fc = 255;
    if (bc > 255)
      bc = 255;
    int r = fc + random.nextInt(bc - fc - 16);
    int g = fc + random.nextInt(bc - fc - 14);
    int b = fc + random.nextInt(bc - fc - 18);
    return new Color(r, g, b);
  }

  /**
   * 生成随机图片(BASE64格式)
   */
  public String getRandcode(HttpServletRequest request, StringBuffer imgBuffer) {
    // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
    Graphics g = image.getGraphics();// 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
    g.fillRect(0, 0, width, height);//图片大小
    g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));//字体大小
    g.setColor(getRandColor(110, 133));//字体颜色
    // 绘制干扰线
    for (int i = 0; i <= lineSize; i++) {
      drowLine(g);
    }
    // 绘制随机字符
    String randomString = "";
    for (int i = 1; i <= stringNum; i++) {
      randomString = drowString(g, randomString, i);
    }
    g.dispose();
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    String encode = null;
    try {
      // 将内存中的图片通过流动形式输出到客户端
      ImageIO.write(image, "JPEG", out);
      encode = "data:image/jpeg;base64,"+Base64.encodeBase64String(out.toByteArray());
      out.close();
    } catch (Exception e) {
      LogHelper.error("登陆控制","验证码生成","将内存中生成的验证码图片输出为BASE64格式编码失败！");
    }
    imgBuffer.append(encode);
    return randomString;
  }


  /**
   * 绘制字符串
   */
  private String drowString(Graphics g, String randomString, int i) {
    g.setFont(getFont());
    g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
        .nextInt(121)));
    String rand = String.valueOf(getRandomString(random.nextInt(RANDOM_STRING.length())));
    randomString += rand;
    g.translate(random.nextInt(3), random.nextInt(3));
    g.drawString(rand, 13 * i, 16);
    return randomString;
  }

  /**
   * 绘制干扰线
   */
  private void drowLine(Graphics g) {
    int x = random.nextInt(width);
    int y = random.nextInt(height);
    int xl = random.nextInt(13);
    int yl = random.nextInt(15);
    g.drawLine(x, y, x + xl, y + yl);
  }

  /**
   * 获取随机的字符
   */
  public String getRandomString(int num) {
    return String.valueOf(RANDOM_STRING.charAt(num));
  }



  public static String randomString(int length){
    return RandomStringUtils.random(length, RANDOM_STRING.toCharArray());
  }
}

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

public class CodeUtil {

  private static int width = 90;// 定义图片的width 90
  private static int height = 20;// 定义图片的height 20
  private static int codeCount = 4;// 定义图片上显示验证码的个数
  private static int xx = 15;
  private static int fontHeight = 18;
  private static int codeY = 16;
  private static char[] codeSequence = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'M', 'N', 'P', 'Q', 'R',
      'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '2', '3', '4', '5', '6', '7', '8', '9'};

  public static Map<String,RenderedImage> codePicMap = new HashMap<>();

  /**
   * 生成一个map集合
   * code为生成的验证码
   * codePic为生成的验证码BufferedImage对象
   *
   * @return
   */
  public static Map<String, Object> generateCodeAndPic() {
    // 定义图像buffer
    BufferedImage buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    // Graphics2D gd = buffImg.createGraphics();
    // Graphics2D gd = (Graphics2D) buffImg.getGraphics();
    Graphics gd = buffImg.getGraphics();
    // 创建一个随机数生成器类
    Random random = new Random();
    // 将图像填充为蓝色
//    gd.setColor(Color.WHITE);
    gd.setColor(new Color(232,240,254));
    gd.fillRect(0, 0, width, height);

    // 创建字体，字体的大小应该根据图片的高度来定。
    Font font = new Font("Fixedsys", Font.BOLD, fontHeight);
    // 设置字体。
    gd.setFont(font);

    // 画边框。
    gd.setColor(Color.BLACK);
    gd.drawRect(0, 0, width - 1, height - 1);

    // 随机产生40条干扰线，使图象中的认证码不易被其它程序探测到。
    gd.setColor(Color.BLACK);
    for (int i = 0; i < 10; i++) {
      int x = random.nextInt(width);
      int y = random.nextInt(height);
      int xl = random.nextInt(12);
      int yl = random.nextInt(12);
      gd.drawLine(x, y, x + xl, y + yl);
    }

    // randomCode用于保存随机产生的验证码，以便用户登录后进行验证。
    StringBuffer randomCode = new StringBuffer();
    int red = 0, green = 0, blue = 0;

    // 随机产生codeCount数字的验证码。
    for (int i = 0; i < codeCount; i++) {
      // 得到随机产生的验证码数字。
      String code = String.valueOf(codeSequence[random.nextInt(31)]);
      // 产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同。
      red = random.nextInt(255);
      green = random.nextInt(255);
      blue = random.nextInt(255);

      // 用随机产生的颜色将验证码绘制到图像中。
      gd.setColor(new Color(red, green, blue));
      gd.drawString(code, (i + 1) * xx, codeY);
      // 将产生的四个随机数组合在一起。
      randomCode.append(code);
    }
    Map<String, Object> map = new HashMap<>();
    //存放验证码
    map.put("code", randomCode);
    //存放生成的验证码BufferedImage对象
    map.put("codePic", buffImg);
    return map;
  }


  public static void main(String[] args) throws Exception {
    //创建文件输出流对象
    OutputStream out = new FileOutputStream("D://img/" + System.currentTimeMillis() + ".jpg");
    Map<String, Object> map = CodeUtil.generateCodeAndPic();
    ImageIO.write((RenderedImage) map.get("codePic"), "jpeg", out);
    System.out.println("验证码的值为：" + map.get("code"));
  }
}