圖片壓縮及字節轉換

/**
	 * 按照 宽高 比例压缩
	 * 
	 * @param imgIs 待压缩图片输入流
	 * @param scale 压缩刻度
	 * @param out 输出
	 * @return 压缩后图片数据
	 * @throws IOException 压缩图片过程中出错
	 */
	public static  File compress(File file, double scale) throws IOException {
		byte[] srcImgData = getBytes(file);
		BufferedImage bi = ImageIO.read(new ByteArrayInputStream(srcImgData));
		int width = (int) (bi.getWidth() / scale); // 源图宽度
		int height = (int) (bi.getHeight() / scale); // 源图高度
 
		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); // 绘制处理后的图
		g.dispose();
 
		ByteArrayOutputStream bOut = new ByteArrayOutputStream();
		ImageIO.write(tag, "png", bOut);
		File lastfile = getFile(bOut.toByteArray(),file);
		return lastfile;
	}

	/**
	 * 文件轉成字節
	 * @param file
	 * @return
	 */
	public static byte[] getBytes(File file) {
		byte[] buffer = null;
		try {
		FileInputStream fis = new FileInputStream(file);
         ByteArrayOutputStream bos = new ByteArrayOutputStream(1000);
         byte[] b = new byte[1000];
         int n;
         while ((n = fis.read(b)) != -1) {
             bos.write(b, 0, n);
         }
         fis.close();
         bos.close();
         buffer = bos.toByteArray();
     } catch (FileNotFoundException e) {
         e.printStackTrace();
     } catch (IOException e) {
         e.printStackTrace();
     }
     return buffer;
	}
	
	/**
	 * 字節轉成文件
	 * @param buffer
	 * @return
	 */
	public static File getFile(byte[] buffer,File file) {
		BufferedOutputStream bos = null;
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(file);
            bos = new BufferedOutputStream(fos);
            bos.write(buffer);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (bos != null) {
                try {
                    bos.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
        }
		return file;
		
	}