图片上传处理Server端

public ActionResult Upload()
{
HttpPostedFileBase file = Request.Files["Fdata"];//接受文件数据
string FileName = Path.GetFileName(file.FileName);//获取文件名
string FileExt = Path.GetExtension(FileName);//获取扩展名
if (FileExt == ".jpg")
{
//file.SaveAs(Request.MapPath("/UploadFile/" + FileName));
string dir = "/UploadFile/" + DateTime.Now.Year + "/" + DateTime.Now.Month + "/" + DateTime.Now.Day + "/";
Directory.CreateDirectory(Request.MapPath(dir));//创建文件夹
string FullDir = dir + GetStreamMD5(file.InputStream) + FileExt;//构建完整路径
file.SaveAs(Request.MapPath(FullDir));//保存完整图片
string ThumbnalPath = dir + Guid.NewGuid() + ".jpg";
MakeThumbnail(Request.MapPath(FullDir), Request.MapPath(ThumbnalPath), 100, 100, "H");//保存缩略图
using (Image img = Image.FromFile(Request.MapPath(ThumbnalPath)))
{
return Json(new
{
imagePath = ThumbnalPath,
width = img.Width,
height = img.Height
});
}

}
else
{
return Content("上传文件失败");
}

}

/// <summary>
/// 计算文件的MD5值
/// </summary>
/// <param name="filepath"></param>
/// <returns></returns>
public static String GetStreamMD5(Stream stream)
{
string strResult = "";
string strHashData = "";
byte[] arrbytHashValue;
System.Security.Cryptography.MD5CryptoServiceProvider oMD5Hasher =
new System.Security.Cryptography.MD5CryptoServiceProvider();
arrbytHashValue = oMD5Hasher.ComputeHash(stream); //计算指定Stream 对象的哈希值
//由以连字符分隔的十六进制对构成的String，其中每一对表示value 中对应的元素；例如“F-2C-4A”
strHashData = System.BitConverter.ToString(arrbytHashValue);
//替换-
strHashData = strHashData.Replace("-", "");
strResult = strHashData;
return strResult;
}

#region 缩略图
/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImagePath">源图路径（物理路径）</param>
/// <param name="thumbnailPath">缩略图路径（物理路径）</param>
/// <param name="width">缩略图宽度</param>
/// <param name="height">缩略图高度</param>
/// <param name="mode">生成缩略图的方式</param>
public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
{
System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);

int towidth = width;
int toheight = height;

int x = 0;
int y = 0;
int ow = originalImage.Width;
int oh = originalImage.Height;

switch (mode)
{
case "HW":  //指定高宽缩放（可能变形）
break;
case "W":   //指定宽，高按比例
toheight = originalImage.Height * width / originalImage.Width;
break;
case "H":   //指定高，宽按比例
towidth = originalImage.Width * height / originalImage.Height;
break;
case "Cut": //指定高宽裁减（不变形）
if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
{
oh = originalImage.Height;
ow = originalImage.Height * towidth / toheight;
y = 0;
x = (originalImage.Width - ow) / 2;
}
else
{
ow = originalImage.Width;
oh = originalImage.Width * height / towidth;
x = 0;
y = (originalImage.Height - oh) / 2;
}
break;
default:
break;
}

//新建一个bmp图片
System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

//新建一个画板
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);

//设置高质量插值法
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

//设置高质量,低速度呈现平滑程度
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

//清空画布并以透明背景色填充
g.Clear(System.Drawing.Color.Transparent);

//在指定位置并且按指定大小绘制原图片的指定部分
g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight), new System.Drawing.Rectangle(x, y, ow, oh), System.Drawing.GraphicsUnit.Pixel);

try
{
//以jpg格式保存缩略图
bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch (System.Exception e)
{
throw e;
}
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
}
#endregion