private BufferedImage getNewImage(MultipartFile oldImage, double width, double height) throws IOException{
		/*srcURl 原图地址；deskURL 缩略图地址；comBase 压缩基数；scale 压缩限制(宽/高)比例*/

		ByteArrayInputStream bais = new ByteArrayInputStream(oldImage.getBytes());
		MemoryCacheImageInputStream mciis = new MemoryCacheImageInputStream(bais);
		Image src = ImageIO.read(mciis);
		double srcHeight = src.getHeight(null);
		double srcWidth = src.getWidth(null);
		double deskHeight = 0;//缩略图高
		double deskWidth  = 0;//缩略图宽
		if (srcWidth>srcHeight) {

			if (srcWidth>width) {
				if (width/height>srcWidth/srcHeight) {
					deskHeight = height;
					deskWidth = srcWidth/(srcHeight/height);
				}
				else {
					deskHeight = width/(srcWidth/srcHeight);
					deskWidth = width;
				}
			}
			else {

				if (srcHeight>height) {
					deskHeight = height;
					deskWidth = srcWidth/(srcHeight/height);
				}else {
					deskHeight=srcHeight;
					deskWidth=srcWidth;
				}

			}

		}
		else if(srcHeight>srcWidth)
		{
			if (srcHeight>(height)) {
				if ((height)/width>srcHeight/srcWidth) {
					deskHeight = srcHeight/(srcWidth/width);
					deskWidth = width;
				}else {
					deskHeight = height;
					deskWidth = (height)/(srcHeight/srcWidth);
				}
			}
			else {
				if (srcWidth>width) {
					deskHeight = srcHeight/(srcWidth/width);
					deskWidth = width;
				}else {
					deskHeight=srcHeight;
					deskWidth=srcWidth;
				}

			}

		}
		else if (srcWidth==srcHeight) {

			if (width>=(height)&&srcHeight>(height)) {
				deskWidth=(height);
				deskHeight=(height);
			}
			else if (width<=(height)&&srcWidth>width) {
				deskWidth=width;
				deskHeight=width;
			}
			else  if (width==(height)&&srcWidth<width) {
				deskWidth=srcWidth;
				deskHeight=srcHeight;
			}
			else {
				deskHeight=srcHeight;
				deskWidth=srcWidth;
			}

		}
		BufferedImage tag = new BufferedImage((int)deskWidth,(int)deskHeight,
				BufferedImage.TYPE_3BYTE_BGR);
		tag.getGraphics().drawImage(src, 0, 0, (int)deskWidth, (int)deskHeight, null); //绘制缩小后的图
		return tag;
	}

上传的MultipartFile

@RequestParam("picFile") MultipartFile file

String originalName = file.getOriginalFilename();
originalName = originalName.toLowerCase();
resp.setType(FilenameUtils.getExtension(originalName));

String id = DateUtils.format(new Date(),"yyyyMMddHHmmssSSS");

resp.setFileName(id + "." + resp.getType());

File path = FileUtils.getFile(imageRootDir);

FileUtils.forceMkdir(path);

File ordinalFile = FileUtils.getFile(path,resp.getFileName());

ImageIO.write(newImage, resp.getType(), ordinalFile);