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

时间：2022-01-31 20:22:04

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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