java 创建缩略图

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import org.apache.commons.lang.StringUtils;

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

/**
 * 
 * 工具类 Copyright (c) 2008 by MTA.
 * 
 */
public class ImageUtils {


	/**
	 * 创建缩略图
	 * 
	 * @param file
	 *            上传的文件流
	 * @param height
	 *            最小的尺寸
	 * @throws IOException
	 */
	public static void createMiniPic(File file, float width, float height,String newImgName)
			throws IOException {
		Image src = javax.imageio.ImageIO.read(file); // 构造Image对象
		int old_w = src.getWidth(null); // 得到源图宽
		int old_h = src.getHeight(null);
		int new_w = 0;
		int new_h = 0; // 得到源图长
		float tempdouble;
		if (old_w >= old_h) {
			tempdouble = old_w / width;
		} else {
			tempdouble = old_h / height;
		}

		if (old_w >= width || old_h >= height) { // 如果文件小于锁略图的尺寸则复制即可
			new_w = Math.round(old_w / tempdouble);
			new_h = Math.round(old_h / tempdouble);// 计算新图长宽
			while (new_w > width && new_h > height) {
				if (new_w > width) {
					tempdouble = new_w / width;
					new_w = Math.round(new_w / tempdouble);
					new_h = Math.round(new_h / tempdouble);
				}
				if (new_h > height) {
					tempdouble = new_h / height;
					new_w = Math.round(new_w / tempdouble);
					new_h = Math.round(new_h / tempdouble);
				}
			}
			BufferedImage tag = new BufferedImage(new_w, new_h, BufferedImage.TYPE_INT_RGB);
			tag.getGraphics().drawImage(src, 0, 0, new_w, new_h, null); // 绘制缩小后的图
			if(StringUtils.isNotBlank(newImgName)){
				final int len = file.getPath().lastIndexOf(File.separator);
				String fn = file.getPath().substring(0, len + 1) + newImgName;
				file = new File(fn);
			}
			FileOutputStream newimage = new FileOutputStream(file); // 输出到文件流
			JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(newimage);
			JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(tag);
			param.setQuality((float) (100 / 100.0), true);// 设置图片质量,100最大,默认70
			encoder.encode(tag, param);
			encoder.encode(tag); // 将JPEG编码
			newimage.close();
		}
	}

	

	public static void main(String[] s) {
		//File srcFile = new java.io.File("d:/我的文档/桌面/桌面文件/sara_and_zack.jpg");
		//ImageUtils.upload("555555.jpg", "d:/我的文档/桌面/桌面文件/", srcFile);
		String ss = "/upload/content/aa.jps";
		String [] aa = ss.split("/");

	}
}