internal static class FileHelper { public static readonly Dictionary<string, string> fileFixDic = new Dictionary<string, string> { {"255216",".jpg"}, {"708783",".swf"}, {"678783",".swf"}, {"707686",".flv"}, }; /// <summary> /// 下载图片 /// </summary> /// <param name="url"></param> /// <returns></returns> public static Image DownLoadImage(string url) { System.Exception exception; return DownLoadImage(url, out exception); } /// <summary> /// 下载图片 /// </summary> /// <param name="url">图片地址</param> /// <param name="exception"></param> /// <param name="isRetry">是否重试</param> /// <param name="reTryNumber">重试次数</param> /// <returns>Image</returns> public static Image DownLoadImage(string url, out System.Exception exception, bool isRetry = true, int reTryNumber = 2) { byte[] data = DownLoadWebFile(url, out exception, isRetry, reTryNumber); return GetImageByByte(data); } /// <summary> /// 下载资源文件 /// </summary> /// <param name="url">资源文件地址</param> /// <returns>byte[]</returns> public static byte[] DownLoadWebFile(string url) { System.Exception exception; return DownLoadWebFile(url, out exception); } /// <summary> /// 下载资源文件 /// </summary> /// <param name="url">资源文件地址</param> /// <param name="exception">Exception</param> /// <param name="isRetry">是否重试，默认是</param> /// <param name="reTryNumber">重试次数 默认2</param> /// <returns>byte[]</returns> public static byte[] DownLoadWebFile(string url, out System.Exception exception, bool isRetry = true, int reTryNumber = 2) { var client = new WebClient(); byte[] data = null; exception = null; while (reTryNumber > 0) { try { data = client.DownloadData(url); reTryNumber = 0; } catch (System.Exception ex) { reTryNumber--; if (reTryNumber == 0) { exception = ex; } } } return data; } /// <summary> /// 检查上传图片文件的像素是否符合 /// </summary> /// <param name="image"></param> /// <returns></returns> public static bool CheckImagePixels(Image image) { //标准图片：1280X1024、800X600、640X480 if (image.Width == 1280 && image.Height == 1024) { return true; } if (image.Width == 800 && image.Height == 600) { return true; } if (image.Width == 640 && image.Height == 480) { return true; } return false; } /// <summary> /// Byet Convert Image /// </summary> /// <param name="bytes"></param> /// <returns></returns> public static Image GetImageByByte(byte[] bytes) { if (null == bytes) { return null; } var ms = new MemoryStream(bytes); return Image.FromStream(ms); } /// <summary> /// 生成缩略图 /// </summary> /// <param name="image">原图</param> /// <param name="width">宽</param> /// <param name="height">高</param> /// <returns>新图</returns> public static Bitmap FixedSize(Image image, int width, int height) { int sourceWidth = image.Width; int sourceHeight = image.Height; int sourceX = 0; int sourceY = 0; int destX = 0; int destY = 0; float nPercent = 0; float nPercentW = 0; float nPercentH = 0; nPercentW = Math.Min((float)width / (float)sourceWidth, 1.0F); nPercentH = Math.Min(((float)height / (float)sourceHeight), 1.0F); //if we have to pad the height pad both the top and the bottom //with the difference between the scaled height and the desired height nPercent = Math.Min(nPercentH, nPercentW); destX = (int)((width - (sourceWidth * nPercent)) / 2); destY = (int)((height - (sourceHeight * nPercent)) / 2); int destWidth = (int)(sourceWidth * nPercent); int destHeight = (int)(sourceHeight * nPercent); Bitmap bmPhoto = new Bitmap(width, height, PixelFormat.Format24bppRgb); bmPhoto.SetResolution(image.HorizontalResolution, image.VerticalResolution); Graphics grPhoto = Graphics.FromImage(bmPhoto); grPhoto.Clear(Color.White); grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic; grPhoto.DrawImage(image, new Rectangle(destX, destY, destWidth, destHeight), new Rectangle(sourceX, sourceY, sourceWidth, sourceHeight), GraphicsUnit.Pixel); grPhoto.Dispose(); return bmPhoto; } /// <summary> /// 获取文件的类型 /// </summary> /// <param name="bytes"></param> /// <returns></returns> public static string GetFileFix(byte[] bytes) { if (bytes.Length < 3) { return string.Empty; } string fileType = string.Format("{0}{1}{2}", bytes[0], bytes[1], bytes[2]); return GetFileFix(fileType); } /// <summary> /// 获取文件的类型 /// </summary> /// <param name="fileStream"></param> /// <returns></returns> public static string GetFileFix(FileStream fileStream) { if (fileStream.Length < 3) { return string.Empty; } return GetFileFix(SteamToBytes(fileStream)); } private static string GetFileFix(string fileType) { foreach (var key in fileFixDic.Keys) { if (fileType.Contains(key)) { return fileFixDic[key]; } } return string.Empty; } /// <summary> /// 将流文件转换为Byte数据 /// </summary> /// <param name="stream"></param> /// <returns></returns> private static byte[] SteamToBytes(Stream stream) { byte[] bytes = new byte[stream.Length]; stream.Read(bytes, 0, bytes.Length); stream.Seek(0, SeekOrigin.Begin); return bytes; } public static void CopyStream(Stream sourceStream, Stream destStream) { if (sourceStream == null) { throw new System.Exception("Source Stream can't be empty."); } if (destStream == null) { throw new System.Exception("destination Stream can't be empty."); } byte[] buffer = new byte[1024 * 8]; int count = 0; while ((count = sourceStream.Read(buffer, 0, buffer.Length)) > 0) { destStream.Write(buffer, 0, count); } } }
