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！