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上传图片用图片文件的对象hash哈希值判断图片是否一样,避免重复提交相同的图片到服务器中

前端:要用到一个插件,点击下载

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>企业用户后台管理系统 - 谭人才招聘系统</title>
    <meta http-equiv=Content-Type content="text/span; charset=gb2312" />
    <meta http-equiv=X-UA-Compatible content="IE=edge" />
    <script src="~/Scripts/jquery-1.8.0.min.js"></script>
    <script type="text/javascript" src="/Scripts/imgareaselect/ajaxfileupload.js"></script>
</head>
<body>
<form name="myform" method="post" id="myform" enctype="multipart/form-data">
 <input type="image" src="" width="185" height="75"  id="logo" />
<input id="image" class="logo_submit_f" type="file" name="image" onchange="ajaxfile();">
</form>

</body>
<script>    
    function ajaxfile() {
        if ($("#image").val() != \'\') {           
            $.ajaxFileUpload({
                url: \'/Company/Home/UploadLogo\',
                type: "post",
                secureuri: false, //是否需要安全协议,一般设置为false
                fileElementId: \'image\', //文件上传域的ID
                dataType: \'json\', //返回值类型 一般设置为json
                data: { },
                success: function (data, status) {  //服务器成功响应处理函数                    
                    $(\'#logo\').attr(\'src\', data.FilePath);
                    $("input[name=\'logo\']").val(data.FilePath);
                }
            })
        }
    }
   
</script>
</html>

  

后端:

        /// <summary>
        /// 上传企业logo
        /// </summary>
        /// <returns></returns>
        public ActionResult UploadLogo()
        {
            HttpFileCollection files = System.Web.HttpContext.Current.Request.Files;
            if (files.Count == 0) return Json("没有没文件", JsonRequestBehavior.AllowGet);
            MD5 hash = new MD5CryptoServiceProvider();
            /**计算指定stream对象的哈希值**/
            byte[] bytehashValue = hash.ComputeHash(files[0].InputStream);
            var HashData = BitConverter.ToString(bytehashValue).Replace("-", "");
            var FileExtension = Path.GetExtension(files[0].FileName);
            var filename = HashData + FileExtension;
            var virtualpath = string.Format("/Upload/Logo/{0}/{1}", DateTime.Now.ToString("yyyyMMdd"), filename);
            //将虚拟路劲转换成物理路劲
            var fullpath = Server.MapPath(virtualpath);
            var path = Path.GetDirectoryName(fullpath);
            if (!Directory.Exists(path))
                Directory.CreateDirectory(path);
            if (!System.IO.File.Exists(fullpath))
                files[0].SaveAs(fullpath);
            var FileSize = this.FileSize(files[0].ContentLength);
            return Json(new { FileName = filename, FilePath = virtualpath, FileSize = FileSize }, "text/html", JsonRequestBehavior.AllowGet);
        }
        /// <summary>
        /// 计算文件大小
        /// </summary>
        /// <param name="bytes"></param>
        /// <returns></returns>
        public string FileSize(long bytes)
        {
            long kblong = 1024;
            long mblong = 1024 * 1024;
            if (bytes < kblong)
                return decimal.Round(decimal.Divide(bytes, kblong), 2).ToString() + "KB";
            else
                return decimal.Round(decimal.Divide(bytes, mblong), 2).ToString() + "MB";
        }

获取文件的hash哈希值方法:

        /// <summary>
        /// 计算文件的hash值 用于比较两个文件是否相同
        /// </summary>
        /// <param name="filePath">文件路径</param>
        /// <returns>文件hash值</returns>
        public static string GetFileHash(string filePath)
        {
            //创建一个哈希算法对象 
            using (HashAlgorithm hash = HashAlgorithm.Create())
            {
                using (FileStream file = new FileStream(filePath, FileMode.Open))
                {
                    //哈希算法根据文本得到哈希码的字节数组 
                    byte[] hashByte= hash.ComputeHash(file);
                    //将字节数组装换为字符串  
                    return BitConverter.ToString(hashByte);
                }
            }
        }

 

做一个记录,没有高水平技术,简简单单写个博客!

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