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!