保存Bitmap到SD卡

/**
 * 保存图片到SD卡(如果有SD卡的话)
 * @param mId
 */
private void saveMerchandiseImgToSD(int mId,String imageName)
{
	FileOutputStream fos = null;
	Bitmap b = PublicMethod.getMerchandiseImage(mId);
	try {
		fos = new FileOutputStream("/sdcard/Discount/" + imageName + ".jpg");
		if (fos != null) {
			b.compress(Bitmap.CompressFormat.JPEG, 90, fos);
			fos.close();
		}
	} catch (Exception e) {
		e.printStackTrace();
	}
}