创建图片的缩略图

import java.awt.Container;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.io.BufferedOutputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class Thumbnail
{

    /**
     * 
     * @param args   
     * @throws IOException 
     * @throws InterruptedException 
     */
    public static void main(String[] args) throws IOException, InterruptedException
    {
        Thumbnail test=new Thumbnail(); 
        test.createThumbnail("C:\\Documents and Settings\\Administrator\\桌面\\a.jpg", 50, 50, 100, "C:\\Documents and Settings\\Administrator\\桌面\\aaa.jpg");

    }

    /**
     * 创建图片的缩略图
     * @param     filename:图片路径
     *             thumbWidth:缩略图宽度
     *             thumbHeight:缩略图高度
     *             quality:缩略图输出质量
     *             outFilename:缩略图保存地址
     *      
     * @throws IOException 
     * @throws InterruptedException 
     */
    private void createThumbnail(String filename, int thumbWidth, int thumbHeight, int quality, String outFilename) 
     throws InterruptedException, FileNotFoundException, IOException 
     { 
     // 根据图片地址filename加载图片
     Image image = Toolkit.getDefaultToolkit().getImage(filename); 
     MediaTracker mediaTracker = new MediaTracker(new Container()); 
     mediaTracker.addImage(image, 0); 
     mediaTracker.waitForID(0); 

     // 确定像素
     double thumbRatio = (double)thumbWidth / (double)thumbHeight; 
     int imageWidth = image.getWidth(null); 
     int imageHeight = image.getHeight(null); 
     double imageRatio = (double)imageWidth / (double)imageHeight; 
     if (thumbRatio < imageRatio) { 
     thumbHeight = (int)(thumbWidth / imageRatio); 
     } else { 
     thumbWidth = (int)(thumbHeight * imageRatio); 
     }

     // 绘制缩略图
     BufferedImage thumbImage = new BufferedImage(thumbWidth, thumbHeight, BufferedImage.TYPE_INT_RGB); 
     Graphics2D graphics2D = thumbImage.createGraphics(); 
     graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR); 
     graphics2D.drawImage(image, 0, 0, thumbWidth, thumbHeight, null);

     // 保存缩略图到保存路径outFilename
     BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(outFilename)); 
     JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); 
     JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(thumbImage); 
     quality = Math.max(0, Math.min(quality, 100)); 
     param.setQuality((float)quality / 100.0f, false); 
     encoder.setJPEGEncodeParam(param); 
     encoder.encode(thumbImage); 
     out.close(); 
     }




}