java实现图片验证码

一、验证码生成类

 package hbi.tech.utils;
 import javax.imageio.ImageIO;
 import java.awt.*;
 import java.awt.image.BufferedImage;
 import java.io.ByteArrayInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Random;

 /**
  * 验证码生成器
  *
  */
 public class SCaptcha {
     // 图片的宽度。
     private int width = 120;
     // 图片的高度。
     private int height = 40;
     // 验证码字符个数
     private int codeCount = 4;
     // 验证码干扰线数
     private int lineCount = 50;
     // 验证码
     private String code = null;
     // 验证码图片Buffer
     private BufferedImage buffImg = null;

     private char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'M', 'N', 'P', 'Q', 'R',
             'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '2', '3', '4', '5', '6', '7', '8', '9' };
     // 生成随机数
     private Random random = new Random();

     public SCaptcha() {
         this.createCode();
     }

     /**
      *
      * @param width 图片宽
      * @param height 图片高
      */
     public SCaptcha(int width, int height) {
         this.width = width;
         this.height = height;
         this.createCode();
     }

     /**
      *
      * @param width 图片宽
      * @param height 图片高
      * @param codeCount 字符个数
      * @param lineCount 干扰线条数
      */
     public SCaptcha(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 codeX = 0;
         int fontHeight = 0;
         fontHeight = height - 5;// 字体的高度
         codeX = width / (codeCount + 3);// 每个字符的宽度

         // 图像buffer
         buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
         Graphics2D g = buffImg.createGraphics();

         // 将图像填充为白色
         g.setColor(Color.WHITE);
         g.fillRect(0, 0, width, height);

         // 创建字体
         ImgFontByte imgFont = new ImgFontByte();
         Font font = imgFont.getFont(fontHeight);
         g.setFont(font);

         StringBuffer randomCode = new StringBuffer();
         // 随机产生验证码字符
         for (int i = 0; i < codeCount; i++) {
             String strRand = String.valueOf(codeSequence[random.nextInt(codeSequence.length)]);
             // 设置字体颜色
             g.setColor(getRandomColor());
             // 设置字体位置
             g.drawString(strRand, (i + 1) * codeX, getRandomNumber(height / 2) + 25);
             randomCode.append(strRand);
         }
         code = randomCode.toString();
     }

     /** 获取随机颜色 */
     private Color getRandomColor() {
         int r = getRandomNumber(255);
         int g = getRandomNumber(255);
         int b = getRandomNumber(255);
         return new Color(r, g, b);
     }

     /** 获取随机数 */
     private int getRandomNumber(int number) {
         return random.nextInt(number);
     }

     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 String getCode() {
         return code;
     }

     /** 字体样式类 */
     class ImgFontByte {
         public Font getFont(int fontHeight) {
             try {
                 Font baseFont = Font.createFont(Font.HANGING_BASELINE, new ByteArrayInputStream(
                         hex2byte(getFontByteStr())));
                 return baseFont.deriveFont(Font.PLAIN, fontHeight);
             } catch (Exception e) {
                 return new Font("Arial", Font.PLAIN, fontHeight);
             }
         }

         private byte[] hex2byte(String str) {
             if (str == null)
                 return null;
             str = str.trim();
             int len = str.length();
             if (len == 0 || len % 2 == 1)
                 return null;

             byte[] b = new byte[len / 2];
             try {
                 for (int i = 0; i < str.length(); i += 2) {
                     b[i / 2] = (byte) Integer.decode("0x" + str.substring(i, i + 2)).intValue();
                 }
                 return b;
             } catch (Exception e) {
                 return null;
             }
         }

         // 字体文件的十六进制字符串
         private String getFontByteStr() {
             //防止报字符串长度过长错误，改为从配置文件读取
             return ReadFontByteProperties.getFontByteStr();
         }
     }
 }

二、读取字体文件类

 package hbi.tech.utils;
 import java.io.InputStream;
 import java.util.Properties;
 public class ReadFontByteProperties {
     static private String fontByteStr = null;
     static {
         loads();
     }
     synchronized static public void loads() {
         if (fontByteStr == null) {
             InputStream is = ReadFontByteProperties.class.getResourceAsStream("/fontByte.properties");
             Properties dbproperties = new Properties();
             try {
                 dbproperties.load(is);
                 fontByteStr = dbproperties.getProperty("fontByteStr").toString();
             } catch (Exception e) {
                 //System.err.println("不能读取属性文件. " + "请确保fontByte.properties在CLASSPATH指定的路径中");
             }
         }
     }
     public static String getFontByteStr() {
         if (fontByteStr == null)
             loads();
         return fontByteStr;
     }
 }

三、生成验证码接口

    /**
      * @author jiaqing.xu@hand-china.com
      * @date 2017/8/23
      * @description 生成图片验证码
      */
     @RequestMapping(value = "/userInfo/verification", method = {RequestMethod.POST, RequestMethod.GET})
     @ResponseBody
     public void verification(HttpServletRequest request, HttpServletResponse response, HttpSession session) throws IOException {
         // 设置响应的类型格式为图片格式
         response.setContentType("image/jpeg");
         // 禁止图像缓存。
         response.setHeader("Pragma", "no-cache");
         response.setHeader("Cache-Control", "no-cache");
         response.setDateHeader("Expires", 0);
         //实例生成验证码对象
         SCaptcha instance = new SCaptcha();
         //将验证码存入session
         session.setAttribute("verification", instance.getCode());
         //向页面输出验证码图片
         instance.write(response.getOutputStream());
     }

将生成的验证码图片存在session中，当用户登录时即可和用户输入的验证码的值进行判断，如果验证相同，则进行后续操作。