简单实现验证码

import java.awt.Color;  
import java.awt.Font;  
import java.awt.Graphics;  
import java.awt.image.BufferedImage;  
import java.util.Random;  
  
/** 
 * 验证码生成器 
 * @see -------------------------------------------------------------------------------------------------------------- 
 * @see 可生成数字、大写、小写字母及三者混合类型的验证码 
 * @see 支持自定义验证码字符数量,支持自定义验证码图片的大小,支持自定义需排除的特殊字符,支持自定义干扰线的数量,支持自定义验证码图文颜色 
 * @see -------------------------------------------------------------------------------------------------------------- 
 * @see 另外,给Shiro加入验证码有多种方式,也可以通过继承修改FormAuthenticationFilter类,通过Shiro去验证验证码 
 * @see 而这里既然使用了SpringMVC,也为了简化操作,就使用此工具生成验证码,并在Controller中处理验证码的校验 
 * @see -------------------------------------------------------------------------------------------------------------- 
 * @create Sep 29, 2013 4:23:13 PM 
 * @author 玄玉<http://blog.csdn.net/jadyer> 
 */  
public class VerifyCodeUtil {  
    /** 
     * 验证码类型为仅数字,即0~9 
     */  
    public static final int TYPE_NUM_ONLY = 0;  
  
    /** 
     * 验证码类型为仅字母,即大小写字母混合 
     */  
    public static final int TYPE_LETTER_ONLY = 1;  
  
    /** 
     * 验证码类型为数字和大小写字母混合 
     */  
    public static final int TYPE_ALL_MIXED = 2;  
  
    /** 
     * 验证码类型为数字和大写字母混合 
     */  
    public static final int TYPE_NUM_UPPER = 3;  
  
    /** 
     * 验证码类型为数字和小写字母混合 
     */  
    public static final int TYPE_NUM_LOWER = 4;  
  
    /** 
     * 验证码类型为仅大写字母 
     */  
    public static final int TYPE_UPPER_ONLY = 5;  
  
    /** 
     * 验证码类型为仅小写字母 
     */  
    public static final int TYPE_LOWER_ONLY = 6;  
  
    private VerifyCodeUtil(){}  
      
    /** 
     * 生成随机颜色 
     */  
    private static Color generateRandomColor() {  
        Random random = new Random();  
        return new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255));  
    }  
      
      
    /** 
     * 生成图片验证码 
     * @param type           验证码类型,参见本类的静态属性 
     * @param length         验证码字符长度,要求大于0的整数 
     * @param excludeString  需排除的特殊字符 
     * @param width          图片宽度(注意此宽度若过小,容易造成验证码文本显示不全,如4个字符的文本可使用85到90的宽度) 
     * @param height         图片高度 
     * @param interLine      图片中干扰线的条数 
     * @param randomLocation 每个字符的高低位置是否随机 
     * @param backColor      图片颜色,若为null则表示采用随机颜色 
     * @param foreColor      字体颜色,若为null则表示采用随机颜色 
     * @param lineColor      干扰线颜色,若为null则表示采用随机颜色 
     * @return 图片缓存对象 
     */  
    public static BufferedImage generateImageCode(int type, int length, String excludeString, int width, int height, int interLine, boolean randomLocation, Color backColor, Color foreColor, Color lineColor){  
        String textCode = generateTextCode(type, length, excludeString);  
        return generateImageCode(textCode, width, height, interLine, randomLocation, backColor, foreColor, lineColor);  
    }  
      
  
    /** 
     * 生成验证码字符串 
     * @param type          验证码类型,参见本类的静态属性 
     * @param length        验证码长度,要求大于0的整数 
     * @param excludeString 需排除的特殊字符（无需排除则为null） 
     * @return 验证码字符串 
     */  
    public static String generateTextCode(int type, int length, String excludeString){  
        if(length <= 0){  
            return "";  
        }  
        StringBuffer verifyCode = new StringBuffer();  
        int i = 0;  
        Random random = new Random();  
        switch(type){  
            case TYPE_NUM_ONLY:  
                while(i < length){  
                    int t = random.nextInt(10);  
                    //排除特殊字符  
                    if(null==excludeString || excludeString.indexOf(t+"")<0) {  
                        verifyCode.append(t);  
                        i++;  
                    }  
                }  
            break;  
            case TYPE_LETTER_ONLY:  
                while(i < length){  
                    int t = random.nextInt(123);  
                    if((t>=97 || (t>=65&&t<=90)) && (null==excludeString||excludeString.indexOf((char)t)<0)){  
                        verifyCode.append((char)t);  
                        i++;  
                    }  
                }  
            break;  
            case TYPE_ALL_MIXED:  
                while(i < length){  
                    int t = random.nextInt(123);  
                    if((t>=97 || (t>=65&&t<=90) || (t>=48&&t<=57)) && (null==excludeString||excludeString.indexOf((char)t)<0)){  
                        verifyCode.append((char)t);  
                        i++;  
                    }  
                }  
            break;  
            case TYPE_NUM_UPPER:  
                while(i < length){  
                    int t = random.nextInt(91);  
                    if((t>=65 || (t>=48&&t<=57)) && (null==excludeString || excludeString.indexOf((char)t)<0)){  
                        verifyCode.append((char)t);  
                        i++;  
                    }  
                }  
            break;  
            case TYPE_NUM_LOWER:  
                while(i < length){  
                    int t = random.nextInt(123);  
                    if((t>=97 || (t>=48&&t<=57)) && (null==excludeString || excludeString.indexOf((char)t)<0)){  
                        verifyCode.append((char)t);  
                        i++;  
                    }  
                }  
            break;  
            case TYPE_UPPER_ONLY:  
                while(i < length){  
                    int t = random.nextInt(91);  
                    if((t >= 65) && (null==excludeString||excludeString.indexOf((char)t)<0)){  
                        verifyCode.append((char)t);  
                        i++;  
                    }  
                }  
            break;  
            case TYPE_LOWER_ONLY:  
                while(i < length){  
                    int t = random.nextInt(123);  
                    if((t>=97) && (null==excludeString||excludeString.indexOf((char)t)<0)){  
                        verifyCode.append((char)t);  
                        i++;  
                    }  
                }  
            break;  
        }  
        return verifyCode.toString();  
    }  
  
    /** 
     * 已有验证码,生成验证码图片 
     * @param textCode       文本验证码 
     * @param width          图片宽度(注意此宽度若过小,容易造成验证码文本显示不全,如4个字符的文本可使用85到90的宽度) 
     * @param height         图片高度 
     * @param interLine      图片中干扰线的条数 
     * @param randomLocation 每个字符的高低位置是否随机 
     * @param backColor      图片颜色,若为null则表示采用随机颜色 
     * @param foreColor      字体颜色,若为null则表示采用随机颜色 
     * @param lineColor      干扰线颜色,若为null则表示采用随机颜色 
     * @return 图片缓存对象 
     */  
    public static BufferedImage generateImageCode(String textCode, int width, int height, int interLine, boolean randomLocation, Color backColor, Color foreColor, Color lineColor){  
        //创建内存图像  
        BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);  
        //获取图形上下文  
        Graphics graphics = bufferedImage.getGraphics();  
        //画背景图  
        graphics.setColor(null==backColor ? generateRandomColor() : backColor);  
        graphics.fillRect(0, 0, width, height);  
        //画干扰线  
        Random random = new Random();  
        if(interLine > 0){  
            int x = 0, y = 0, x1 = width, y1 = 0;  
            for(int i=0; i<interLine; i++){  
                graphics.setColor(null==lineColor ? generateRandomColor() : lineColor);  
                y = random.nextInt(height);  
                y1 = random.nextInt(height);  
                graphics.drawLine(x, y, x1, y1);  
            }  
        }  
        //字体大小为图片高度的80%  
        int fsize = (int)(height * 0.8);  
        int fx = height - fsize;  
        int fy = fsize;  
        //设定字体  
        graphics.setFont(new Font("Default", Font.PLAIN, fsize));  
        //写验证码字符  
        for(int i=0; i<textCode.length(); i++){  
            fy = randomLocation ? (int)((Math.random()*0.3+0.6)*height) : fy;  
            graphics.setColor(null==foreColor ? generateRandomColor() : foreColor);  
            //将验证码字符显示到图象中  
            graphics.drawString(textCode.charAt(i)+"", fx, fy);  
            fx += fsize * 0.9;  
        }  
        graphics.dispose();  
        return bufferedImage;  
    }  
}  

/**
 * 小工具类
 * @author Administrator
 *
 */
@RestController
public class UtilController {

	@Resource
	private UtilDaoService utilDaoService;
	Logger logging=Logger.getLogger(UtilController.class);
	    /** 
	     * 获取验证码图片和文本(验证码文本会保存在HttpSession中) 
	     */  
		/**
		 * 验证码生成类
		 * @param request
		 * @param response
		 * @throws IOException
		 */
	    @RequestMapping("getVerifyCodeImage")  
	    public void getVerifyCodeImage(HttpServletRequest request, HttpServletResponse response) throws IOException {  
	        //设置页面不缓存  
	        response.setHeader("Pragma", "no-cache");  
	        response.setHeader("Cache-Control", "no-cache");  
	        response.setDateHeader("Expires", 0);  
	        String verifyCode = VerifyCodeUtil.generateTextCode(VerifyCodeUtil.TYPE_NUM_ONLY, 4, null);  
	        //将验证码放到HttpSession里面  
	        request.getSession().setAttribute("verifyCode", verifyCode);  
	       logging.info("本次生成的验证码为[" + verifyCode + "],已存放到HttpSession中");  
	        //设置输出的内容的类型为JPEG图像  
	        response.setContentType("image/jpeg");
	        BufferedImage bufferedImage = VerifyCodeUtil.generateImageCode(verifyCode, 90, 30, 3, true, Color.WHITE, Color.BLACK, null);  
	        //写给浏览器  
	        ImageIO.write(bufferedImage, "JPEG", response.getOutputStream());  
	    }

  
  
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