验证码图片_ImageUtil

package ;

import java.awt.AlphaComposite;   
import java.awt.Color;   
import java.awt.Font;   
import java.awt.Graphics;
import java.awt.Graphics2D;   
import java.awt.Image;   
import java.awt.geom.AffineTransform;   
import java.awt.image.AffineTransformOp;   
import java.awt.image.BufferedImage;   
import java.io.File;   
import java.io.IOException;   
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;   

  
/**  
 * 图片处理 
 * @author 
 *  
 */  
public final class ImageUtil {   
    /**  
     * 图片水印  
     * @param pressImg 水印图片  
     * @param targetImg 目标图片  
     * @param x 修正值 默认在中间  
     * @param y 修正值 默认在中间  
     * @param alpha 透明度  
     */  
    public  static void pressImage(String pressImg, String targetImg, final int x, final int y,final float alpha) {   
        try {   
            File img = new File(targetImg);   
            Image src = ImageIO.read(img);   
            int wideth = src.getWidth(null);   
            int height = src.getHeight(null);   
            BufferedImage image = new BufferedImage(wideth, height, BufferedImage.TYPE_INT_RGB);   
            Graphics2D g = image.createGraphics();   
            g.drawImage(src, 0, 0, wideth, height, null);   
            //水印文件   
            Image srcBiao = ImageIO.read(new File(pressImg));   
            int widethBiao = srcBiao.getWidth(null);   
            int heightBiao = srcBiao.getHeight(null);   
            g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));   
            g.drawImage(srcBiao, (wideth - widethBiao) / NumberUtils.INT_2, (height - heightBiao) / NumberUtils.INT_2, widethBiao, heightBiao, null);   
            //水印文件结束   
            g.dispose();   
            ImageIO.write((BufferedImage) image, "jpg", img);   
        } catch (Exception e) {   
            e.printStackTrace();   
        }   
    }   
  
    /**  
     * 文字水印  
     * @param pressText 水印文字  
     * @param targetImg 目标图片  
     * @param fontName 字体名称  
     * @param fontStyle 字体样式  
     * @param color 字体颜色  
     * @param fontSize 字体大小  
     * @param x 修正值  
     * @param y 修正值  
     * @param alpha 透明度  
     */  
    public static void pressText(String pressText, String targetImg, String fontName, int fontStyle, Color color, int fontSize, int x, int y, float alpha) {   
        try {   
            File img = new File(targetImg);   
            Image src = ImageIO.read(img);   
            int width = src.getWidth(null);   
            int height = src.getHeight(null);   
            BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);   
            Graphics2D g = image.createGraphics();   
            g.drawImage(src, 0, 0, width, height, null);   
            g.setColor(color);   
            g.setFont(new Font(fontName, fontStyle, fontSize));   
            g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));   
            g.drawString(pressText, (width - (getLength(pressText) * fontSize)) / NumberUtils.INT_2 + x, (height - fontSize) /NumberUtils.INT_2 + y);   
            g.dispose();   
            ImageIO.write((BufferedImage) image, "jpg", img);   
        } catch (Exception e) {   
            e.printStackTrace();   
        }   
    }   
  
    /**  
     * 缩放  
     * @param filePath 图片路径  
     * @param height 高度  
     * @param width 宽度  
     * @param bb 比例不对时是否需要补白  
     */  
    public static void resize(String filePath, int height, int width, boolean bb) {   
        try {   
            double ratio = 0.0; //缩放比例    
            File f = new File(filePath);   
            BufferedImage bi = ImageIO.read(f);   
            Image itemp = bi.getScaledInstance(width, height, bi.SCALE_SMOOTH);   
            //计算比例   
            if ((bi.getHeight() > height) || (bi.getWidth() > width)) {   
                if (bi.getHeight() > bi.getWidth()) {   
                    ratio = (new Integer(height)).doubleValue() / bi.getHeight();   
                } else {   
                    ratio = (new Integer(width)).doubleValue() / bi.getWidth();   
                }   
                AffineTransformOp op = new AffineTransformOp(AffineTransform.getScaleInstance(ratio, ratio), null);   
                itemp = op.filter(bi, null);   
            }   
            if (bb) {   
                BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);   
                Graphics2D g = image.createGraphics();   
                g.setColor(Color.white);   
                g.fillRect(0, 0, width, height);   
                if (width == itemp.getWidth(null))  {
                	g.drawImage(itemp, 0, (height - itemp.getHeight(null)) / NumberUtils.INT_2, itemp.getWidth(null), itemp.getHeight(null), Color.white, null);   
                }else{
                	g.drawImage(itemp, (width - itemp.getWidth(null)) / NumberUtils.INT_2, 0, itemp.getWidth(null), itemp.getHeight(null), Color.white, null);   
                }  
                g.dispose();   
                itemp = image;   
            }   
            ImageIO.write((BufferedImage) itemp, "jpg", f);   
        } catch (IOException e) {   
            e.printStackTrace();   
        }   
    }   
  /*
    public static void main(String[] args) throws IOException {   
        //pressImage("G:\\imgtest\\sy.jpg", "G:\\imgtest\\test1.jpg", 0, 0, 0.5f);   
        //pressText("我是文字水印", "G:\\imgtest\\test1.jpg", "黑体", 36, Color.white, 80, 0, 0, 0.3f);   
    	resize("文件地址",10,1,true);
    }   
  */
    /**
     * 获取长度
     * @param text 文本
     * @return int
     */
    public static int getLength(String text) {   
        int length = 0;   
        for (int i = 0; i < text.length(); i++) {   
            if (new String(text.charAt(i) + "").getBytes().length > 1) {   
                length += NumberUtils.INT_2;   
            } else {   
                length += 1;   
            }   
        }   
        return length / NumberUtils.INT_2;   
    }  
    
    
        // -----------------------------验证码--------------------------------
 		// 验证码图片中可以出现的字符集，可根据需要修改

	    /**
	     *  * 功能：生成彩色验证码图片 参数width为生成图片的宽度，参数height为生成图片的高度 参数os为页面的输出流
	     * @param width 宽
	     * @param height 高
	     * @param os 流
	     * @return 文字
	     */
 		public static String getCertPic(int width, int height, OutputStream os) {
 			final int aw=60;
 			final int ah=20;
 			
 			char[] mapTable = { 'a', 'A', 'b', 'B', 'c', 'C', 'd', 'D', 'e', 'E','f', 'F',
 								'g', 'G', 'h', 'H', 'i', 'J', 'k', 'K', 'L', 'M','N', 'P', 'Q', 'R', 'S', 
 								'T', 'U', 'V', 'W', 'X', 'Y', 'Z','2', '3', '4', '5', '6', '7', '8', '9' };
 			if (width <= 0){
 				width = aw;
 			}
 			if (height <= 0){
 				height = ah;
 			}
 			BufferedImage image = new BufferedImage(width, height,
 					BufferedImage.TYPE_INT_RGB);
 			// 获取图形上下文
 			Graphics g = image.getGraphics();
 			// 设定背景色
 			final int color=0xdcdcdc;
 			g.setColor(new Color(color));
 			g.fillRect(0, 0, width - 1, height - 1);
 			// 取随机产生的验证码
 			String strEnsure = "";
 			// 4代表4位验证码，如果要生成更多位的验证码，则加大数值
 			
 			final int size=4;
 			for (int i = 0; i < size; i++) {
 				strEnsure += mapTable[(int) (mapTable.length * Math.random())];
 			}
 			// 将验证码显示到图像中，如果要生成更多位的验证码，增加drawString语句
 			final int fontSize=18;
 			g.setColor(Color.black);
 			g.setFont(new Font("Atlantic Inline", Font.PLAIN, fontSize));
 			String str = strEnsure.substring(0, 1);
 			g.drawString(str, new Integer("8"), new Integer("17"));

 			g.setColor(Color.red);
 			str = strEnsure.substring(1, NumberUtils.INT_2);
 			
 			g.drawString(str, new Integer("20"),new Integer("15"));

 			g.setColor(Color.DARK_GRAY);
 			str = strEnsure.substring(NumberUtils.INT_2, NumberUtils.INT_3);
 			g.drawString(str, new Integer("35"), new Integer("18"));

 			g.setColor(Color.red);
 			str = strEnsure.substring(new Integer("3"), new Integer("4"));
 			g.drawString(str, new Integer("45"), new Integer("15"));

 			Random rand = new Random();

 			// 随机产生10个干扰点，如果要更多干扰点只需加大i的上限值
 			g.setColor(Color.black);
 			final int length=30;
 			for (int i = 0; i < length; i++) {
 				int x = rand.nextInt(width);
 				int y = rand.nextInt(height);
 				g.drawOval(x, y, 1, 1);
 				// g.drawLine(x, y, 1, 1);
 			}
 			// 释放图形上下文
 			g.dispose();
 			try {
 				// 输出图像到页面
 				ImageIO.write(image, "JPEG", os);
 			} catch (IOException e) {
 				return "";
 			}
 			return strEnsure;
 		}
}  



使用：
    /**
     * 获取验证码
     */
    public void getYzm(){
    	try{
    		HttpSession session = getSession();
    		String str = ImageUtil.getCertPic(0, 0, ServletActionContext.getResponse().getOutputStream());
    		session.setAttribute("loginyzm", str);
    	}catch(Exception e){
    		e.printStackTrace();
    	}
    }