java代码实现图片压缩

public class Demo {
	public static String zipImageFile(String oldFile, int width, int height, float quality, String smallIcon) {
		if (oldFile == null) {
			return null;
		}
		String newImage = null;
		try {
			/** 对服务器上的临时文件进行处理 */
			Image srcFile = ImageIO.read(new File(oldFile));
			/** 宽,高设定 */
			BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
			tag.getGraphics().drawImage(srcFile, 0, 0, width, height, null);
			String filePrex = oldFile.substring(0, oldFile.indexOf('.'));
			/** 压缩后的文件名 */
			newImage = filePrex + smallIcon + oldFile.substring(filePrex.length());
			/** 压缩之后临时存放位置 */
			FileOutputStream out = new FileOutputStream(newImage);
			JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
			JPEGEncodeParam jep = JPEGCodec.getDefaultJPEGEncodeParam(tag);
			/** 压缩质量 */
			jep.setQuality(quality, true);
			encoder.encode(tag, jep);
			out.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return newImage;
	}

	/**
	 * 061 保存文件到服务器临时路径(用于文件上传) 062
	 * 
	 * @param fileName
	 *            063
	 * @param is
	 *            064
	 * @return 文件全路径 065
	 */

	public static String writeFile(String fileName, InputStream is) {
		if (fileName == null || fileName.trim().length() == 0) {
			return null;
		}
		try {
			/** 首先保存到临时文件 */
			FileOutputStream fos = new FileOutputStream(fileName);
			byte[] readBytes = new byte[512];// 缓冲大小
			int readed = 0;
			while ((readed = is.read(readBytes)) > 0) {
				fos.write(readBytes, 0, readed);
			}
			fos.close();
			is.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return fileName;
	}

	/**
	 *  等比例压缩算法： 算法思想：根据压缩基数和压缩比来压缩原图，生产一张图片效果最接近原图的缩略图
	 * 
	 * @param srcURL
	 *            原图地址 
	 * @param deskURL
	 *            缩略图地址 
	 * @param comBase
	 *            压缩基数 
	 * @param scale
	 *            压缩限制(宽/高)比例 一般用1：
	 *            当scale>=1,缩略图height=comBase,width按原图宽高比例;若scale<1,缩略图width
	 *            =comBase,height按原图宽高比例 
	 * @throws Exception
	 *             
	 * @author shenbin 
	 * @createTime 2014-12-16 
	 * @lastModifyTime 2014-12-16 
	 */

	public static void saveMinPhoto(String srcURL, String deskURL, double comBase, double scale) throws Exception {
		File srcFile = new java.io.File(srcURL);
		Image src = ImageIO.read(srcFile);
		int srcHeight = src.getHeight(null);
		int srcWidth = src.getWidth(null);
		int deskHeight = 0;// 缩略图高
		int deskWidth = 0;// 缩略图宽
		double srcScale = (double) srcHeight / srcWidth;
		/** 缩略图宽高算法 */
		if ((double) srcHeight > comBase || (double) srcWidth > comBase) {
			if (srcScale >= scale || 1 / srcScale > scale) {
				if (srcScale >= scale) {
					deskHeight = (int) comBase;
					deskWidth = srcWidth * deskHeight / srcHeight;
				} else {
					deskWidth = (int) comBase;
					deskHeight = srcHeight * deskWidth / srcWidth;
				}
			} else {
				if ((double) srcHeight > comBase) {
					deskHeight = (int) comBase;
					deskWidth = srcWidth * deskHeight / srcHeight;
				} else {
					deskWidth = (int) comBase;
					deskHeight = srcHeight * deskWidth / srcWidth;
				}
			}
		} else {
			deskHeight = srcHeight;
			deskWidth = srcWidth;
		}
		BufferedImage tag = new BufferedImage(deskWidth, deskHeight, BufferedImage.TYPE_3BYTE_BGR);
		tag.getGraphics().drawImage(src, 0, 0, deskWidth, deskHeight, null); // 绘制缩小后的图
		FileOutputStream deskImage = new FileOutputStream(deskURL); // 输出到文件流
		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(deskImage);
		encoder.encode(tag); // 近JPEG编码
		deskImage.close();
	}

	public static void main(String args[]) throws Exception {
		Demo.zipImageFile("e:/1.jpg", 1280, 1280, 1f, "x2");
		Demo.saveMinPhoto("f:/QQ文件/1.bmp", "e:/2.bmp", 1000, 0.9d);
	}
}