图片压缩

package com.data.demo;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.awt.image.CropImageFilter;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageFilter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import javax.imageio.ImageIO;

import com.data.common.utils.SmtpfException;

public class Imgtools{

	/**
	 * 按照高宽比列压缩图片
	 * @param img
	 * @param width
	 * @param height
	 * @param os
	 */
	public static void thumbnail_w_h(File fileimg,int width,int height,
			OutputStream os){
			
			BufferedImage bi;
			try {
				bi = ImageIO.read(fileimg);
				double srcWidth = bi.getWidth(); // 源图宽度
				double srcHeight = bi.getHeight(); // 源图高度
				double scale	 = -1;
				if(width>0){
					scale = width/srcWidth;
				}
				if(height>0){
					scale = height / srcHeight;
				}if(width>0&&height>0){//按照小比列压缩
					scale = height/srcHeight < width/srcWidth ? height/srcHeight:width/srcWidth;
					thumbnail(fileimg,(int)(srcWidth*scale),(int)(srcHeight * scale),os);	
			} 
			} catch (IOException e) {
				e.printStackTrace();
			}		
	}
	
	/**
	 * 按照固定宽高原图压缩
	 * 
	 * @param fileimg
	 * @param width
	 * @param height
	 * @param os
	 * @throws IOException
	 */
	public static void thumbnail(File fileimg, int width, int height, OutputStream os) throws IOException  {
		BufferedImage bi = ImageIO.read(fileimg);
		Image image = bi.getScaledInstance(width, height, Image.SCALE_SMOOTH);
		BufferedImage tag =new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		Graphics g = tag.getGraphics();
		g.setColor(Color.RED);
		g.drawImage(image, 0, 0, null);
		g.dispose();//释放Graphics 对象。
		ImageIO.write(tag, "JPEG", os);
	}
	/**
	 * 按照宽高剪接
	 * @param args
	 */
	public static void cut_w_h(File fileimg, int destwidth,int desthegiht,OutputStream os){
		cut_w_h(fileimg, 0, 0, destwidth, desthegiht, os);
	}
	public static void cut_w_h(File fileimg, int width, int height, int destwidth,int desthegiht,OutputStream os){
		Image img;
		ImageFilter filter;
		//读取源图片
		try {
			BufferedImage b1 =ImageIO.read(fileimg);
			int srcWidth = b1.getWidth(); // 源图宽度
            int srcHeight = b1.getHeight(); // 源图高度
            if(srcWidth>=destwidth&&srcHeight>=desthegiht){
            	Image image = b1.getScaledInstance(srcWidth, srcHeight, Image.SCALE_DEFAULT);//创建此图像的缩放版本。	
            	filter = new CropImageFilter(width, height,destwidth ,desthegiht);//裁剪图像
            	img = Toolkit.getDefaultToolkit().createImage( new FilteredImageSource(image.getSource(), filter));
            	BufferedImage tag = new BufferedImage(destwidth, desthegiht,
                        BufferedImage.TYPE_INT_RGB);
            	Graphics g = tag.getGraphics();
                g.drawImage(img, 0, 0, null); // 绘制截取后的图
                g.dispose();
                // 输出为文件
                ImageIO.write(tag, "JPEG", os);
            }
            
			
		} catch (IOException e) {
			e.printStackTrace();
		}
		
		
	}
	 public static void main(String[] args) throws IOException {
	        File img = new File("e:\\a\\a.jpg");
	        FileOutputStream fos = new FileOutputStream("e:\\a\\b.jpg");
	        //Imgtools.thumbnail(img, 100, 100, fos);
	       // Imgtools.cut_w_h(img, 230, 200, fos);
	        Imgtools.thumbnail_w_h(img, 80,20, fos);
	    }
}