.Net文件上传和下载-526互联

1.前端控件代码

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script src="js/jquery-3.4.1.min.js" type="text/javascript" charset="utf-8"></script>
</head>

<style>
#FileDown:focus {
outline:none;border: 2px solid #C0C0C0;border-left: 5px solid rgb(0,139,229);
}
#FileDown{
width: 500px;height: 30px;border: 1px solid #E7EAEC; border-left: 5px solid rgb(0,139,229);
}
</style>

<style>
a[class="button-selectimg"] {
color: black; padding: 4px 6px; background-color: rgb(0,139,229);border-radius: 2px; text-decoration: none;
}
input[id="avatval"] {
padding: 3px 6px; padding-left: 10px;border: 1px solid #E7EAEC; width: 500px;height: 29.8px; line-height: 25px;border-left: 7px solid rgb(0,139,229);background: #FAFAFB;border-radius: 2px;
}
input[type="file"] {
border: 0px; display: none;
}
#avatval:focus {
outline:none;border: 2px solid #FAFAFB;border-left: 5px solid rgb(0,139,229);
}
</style>
<body>
<div id="xiaZai">
<input type="text" name="FileDown" placeholder="无可下载文件···" id="FileDown" value="" readonly="readonly" />
<INPUT id="downFile" style="margin: 0px 0px 5px 0px;width: 100px;height: 30px;" class="l-btn-text btn c" value="下载文件" type="button"/>
</div>
<div class="input-file">
<input type="text" id="avatval" placeholder="可选择上传文件···" readonly="readonly" />
<input type="file" name="avatar" id="avatar"/>
<INPUT id="upFile" style="margin: 0px 0px 5px 0px;width: 100px;height: 30px;" class="l-btn-text btn c" value="上传" type="button"/>
</div>

</body>
</html>

<script type="text/javascript">
function Get(){
debugger
var files = $('input[name="avatar"]').prop('files');
alert(files);
var list=eval(files);
for(var i=0;i<list.length;i++){
alert(list[i].type)
}
}
$(function(){

$("#avatval").click(function(){
$("input[type='file']").trigger('click');
});
$("input[type='file']").change(function(){
$("#avatval").val($(this).val());
});
});
</script>

<script type="text/javascript">
$("#downFile").click(function(){
var BillNo=BC_PS_SS_AppealBase.getFieldValue("BillNo");
var EmpNo=UCML.UserInfo.getUserId();
var isV="2";
var url = UCMLLocalResourcePath+"ImgHandler.ashx?BillNo="+BillNo+"&isV="+isV+"&EmpNo="+EmpNo;
window.open(url);
})
</script>

<script type="text/javascript">
$("#upFile").click(function(){
var files = $('input[name="avatar"]').prop('files');
var flies=$('#avatar').get(0).files[0];
var fileType="";
var fileName="";
var fileSize="";
var isV="1";
var list=eval(files);
for(var i=0;i<list.length;i++){
fileType=list[i].type;
fileName=list[i].name;
fileSize=list[i].size;
}
var formData = new FormData();
formData.append("fileType",fileType);//上传一个files对象
formData.append("fileName",fileName);
formData.append("fileSize",fileSize);
formData.append("isV",isV);
formData.append("file",$("#avatar").get(0).files[0]);
$.ajax({//此处可以换成其它请求方式
url: '../../ImgHandler.ashx',
dataType: "json",
type: "post",
data: formData,
processData: false,//不去处理发送的数据
contentType: false,//不去设置Content-Type请求头
error: function (res) {
//alert(res.message);
return;
},
success: function (res) {
//alert(res.message);
return;
}
})
})
</script>

2.定义ImgHandler.ashx页面（页面代码）

<%@ WebHandler Language="C#" CodeBehind="ImgHandler.ashx.cs" Class="UCMLCommon.ImgHandler" %>
3.定义ImgHandler.ashx.cs类（类后端代码）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Newtonsoft.Json;
using System.Data.SqlClient;
using Newtonsoft.Json.Linq;
using Newtonsoft.Json;
using System.IO;
using System.Threading;

namespace UCMLCommon
{

public enum CodeStatus
{
error = 0,
success = 1
}

public class Message
{
//1:成功 0:失败
public int code { get; set; }
public string message { get; set; }

public Message(CodeStatus code, string message)
{
this.code = (int)code;
this.message = message;
}

}

/// <summary>
/// ImgHandler 的摘要说明
/// PM_ProduceSignSampleImg图片上传
/// </summary>
public class ImgHandler : IHttpHandler
{

public void ProcessRequest(HttpContext context)
{
//返回信息
Message meg = new Message(CodeStatus.error, "");

HttpFileCollection files = context.Request.Files;//获取文件信息

var fileName = context.Request.Params["fileName"];
var BillNo = context.Request.Params["BillNo"];
var EmpNo = context.Request.Params["EmpNo"];
var fileSize = context.Request.Params["fileSize"];
var NodeEmpOID = "";
var isV = context.Request.Params["isV"];
var isSava = 0;//判断是否存在该记录文件
//DAL
DBLayer.PS_BS_Employee dal = new DBLayer.PS_BS_Employee();
Thread.Sleep(100);
if (BillNo != "" && EmpNo != "")
{
string data = @" select COUNT(*) as isSava,PS_SS_AppealNodeEmpOID from PS_SS_Appeal Appeal inner join PS_SS_AppealNode Node on Appeal.PS_SS_AppealOID=Node.PS_SS_Appeal_FK
inner join PS_SS_AppealNodeEmp Emp on Node.PS_SS_AppealNodeOID=Emp.PS_SS_AppealNode_FK
where BillNo='" + BillNo + "' and FlowNode=1 and OpUser='" + EmpNo + "' group by PS_SS_AppealNodeEmpOID";
string DataNodeEmpOID = JsonConvert.SerializeObject(dal.ExecuteQuery(data));
JArray DataNodeEmpOIDs = (JArray)JsonConvert.DeserializeObject(DataNodeEmpOID);
for (int i = 0; i < DataNodeEmpOIDs.Count; i++)
{
NodeEmpOID = DataNodeEmpOIDs[i]["PS_SS_AppealNodeEmpOID"].ToString();
}

string sqlIsSava = @" select COUNT(*) as isSava from PS_SS_AppealNodeEmpAtt Att inner join PS_SS_AppealNodeEmp Emp on Att.PS_SS_AppealNodeEmp_FK=Emp.PS_SS_AppealNodeEmpOID
inner join PS_SS_AppealNode Node on Emp.PS_SS_AppealNode_FK=Node.PS_SS_AppealNodeOID
inner join PS_SS_Appeal Appeal on Node.PS_SS_Appeal_FK=Appeal.PS_SS_AppealOID
where Appeal.BillNo='" + BillNo + "' and Node.FlowNode=1 and Emp.OpUser='" + EmpNo + "'";
string DataIsSava = JsonConvert.SerializeObject(dal.ExecuteQuery(sqlIsSava));
JArray DataIsSavas = (JArray)JsonConvert.DeserializeObject(DataIsSava);
for (int i = 0; i < DataIsSavas.Count; i++)
{
isSava = Convert.ToInt32(DataIsSavas[i]["isSava"]);
}
}

if (isV == "1")//上传
{
HttpPostedFile uploadFile = context.Request.Files[0];
var OID = Guid.NewGuid().ToString();
#region 文件上传
if (files.Count != 0)
{
try
{
var TypeList = fileName.Split('.');
var fileType = "." + TypeList[1];
var pathUrls = Path.GetFileName(files[0].FileName);
//自定义路径
string path = Path.Combine(System.Web.HttpContext.Current.Request.MapPath("upload")+ "\\"+ OID, pathUrls);// System.Web.HttpContext.Current.Server.MapPath("upload") + "\\"+fileName;
var pathList = path.Split('u');
var PathUrl = "u" + pathList[1];
//添加记录到数据库
if (isSava < 1)
{
string sql = @" insert into PS_SS_AppealNodeEmpAtt([PS_SS_AppealNodeEmpAttOID], [AttachmentName], [FileType], [FilePath], [PS_SS_AppealNodeEmp_FK])
values(NEWID(),'" + fileName + "','" + fileType + "','" + PathUrl + "','" + NodeEmpOID + "')";
dal.ExecuteQuery(sql);
}
else
{
string sql = @" update PS_SS_AppealNodeEmpAtt set AttachmentName='" + fileName + "',FileType='" + fileType + "',FilePath='" + PathUrl + "' where PS_SS_AppealNodeEmp_FK='" + NodeEmpOID + "'";
dal.ExecuteQuery(sql);
}
//上传文件到服务器目录
Byte[] bytes = new byte[uploadFile.ContentLength];
uploadFile.InputStream.Read(bytes, 0, uploadFile.ContentLength);
//判断是否存在这保存目录，没有则创建
DirectoryInfo dir = new DirectoryInfo(System.Web.HttpContext.Current.Request.MapPath("upload") + "\\" + OID);
if (!dir.Exists)
{
dir.Create();
}

FileStream fs = new FileStream(path, FileMode.Create);
if (uploadFile.ContentLength <= 10 * 1024 * 1024)//文件小于10M时使用同步写方式
{
fs.Write(bytes, 0, bytes.Length);
fs.Flush();
fs.Close();
}
else //文件大于10M时使用异步写方式
{
fs.BeginWrite(bytes, 0, bytes.Length, BigFileWrite, fs);
}
meg.message = "上传成功!";
context.Response.ContentType = "application/json";
context.Response.Write(JsonConvert.SerializeObject(meg));
context.Response.End();
}
catch (Exception ex)
{
meg.message =ex.Message;
context.Response.ContentType = "application/json";
context.Response.Write(JsonConvert.SerializeObject(meg));
context.Response.End();
throw;
}
//files[0].SaveAs(path);
}
else
{
if (fileName != "")
{
meg.message = "不支持该类型文件，上传失败!";
context.Response.ContentType = "application/json";
context.Response.Write(JsonConvert.SerializeObject(meg));
context.Response.End();
}
}
#endregion
}
if (isV == "2") //下载
{
#region 下载
if (BillNo != "")//判断流水号
{
string sql = @" select AttachmentName,FilePath,FileType from PS_SS_Appeal Appeal
inner join PS_SS_AppealNode Node on Appeal.PS_SS_AppealOID=Node.PS_SS_Appeal_FK
inner join PS_SS_AppealNodeEmp Emp on Node.PS_SS_AppealNodeOID=Emp.PS_SS_AppealNode_FK
inner join PS_SS_AppealNodeEmpAtt Att on Emp.PS_SS_AppealNodeEmpOID=Att.PS_SS_AppealNodeEmp_FK
where BillNo='" + BillNo + "'";
string Jsondata = JsonConvert.SerializeObject(dal.ExecuteQuery(sql));
JArray Jsondatas = (JArray)JsonConvert.DeserializeObject(Jsondata);
var AttachmentName = "";//文件名
var FilePath = "";//文件路径
var FileType = "";//文件类型
for (int i = 0; i < Jsondatas.Count; i++)
{
AttachmentName = Jsondatas[i]["AttachmentName"].ToString();
FilePath = Jsondatas[i]["FilePath"].ToString();
FileType = Jsondatas[i]["FileType"].ToString();
}
string SavePath = System.Web.HttpContext.Current.Server.MapPath(context.Request.ApplicationPath + "//" + FilePath);
FileInfo fileInfo = new FileInfo(SavePath);
if (fileInfo.Exists)
{
var fullPath = SavePath;
FileStream fs = new FileStream(fullPath, FileMode.Open);
context.Response.Clear();
byte[] buffer = new byte[fs.Length];
fs.Read(buffer, 0, buffer.Length);
context.Response.AppendHeader("Content-type", GetMIMEType(AttachmentName));
context.Response.BinaryWrite(buffer);

context.Response.AppendHeader("Content-Disposition", "attachment;filename=" + FileNameEncode(AttachmentName));
fs.Close();

//FileStream fs = new FileStream(SavePath, FileMode.Open);
//context.Response.Clear();
//byte[] buffer = new byte[fs.Length];
//fs.Read(buffer, 0, buffer.Length);
//context.Response.AppendHeader("Content-type", GetMIMEType(AttachmentName));
//context.Response.BinaryWrite(buffer);
//context.Response.AppendHeader("Content-Disposition", "attachment;filename=" + FileNameEncode(AttachmentName));
//fs.Close();
}
else
{
meg.message = "file not found!";
context.Response.ContentType = "application/json";
context.Response.Write(JsonConvert.SerializeObject(meg));
context.Response.End();
}
}
#endregion
}
}
//文件名URL编码
private string FileNameEncode(string orign)
{
string encoded = HttpUtility.UrlEncode(orign, new System.Text.UTF8Encoding());
encoded = encoded.Replace("+", "%20");
return encoded;
}
public bool IsReusable
{
get
{
return false;
}
}
//得到资源MIME类型
private string GetMIMEType(string fileName)
{
string extName = FileNameEncode(fileName);
if (!String.IsNullOrEmpty(extName))
{
return "application/octet-stream";
}
string mime = "";
switch (extName.ToLower())
{
case ".png": mime = "image/png"; break;
case ".bmp": mime = "image/bmp"; break;
case ".jpeg": mime = "image/jpeg"; break;
case ".jpg": mime = "image/jpg"; break;
case ".gif": mime = "image/gif"; break;
case ".txt": mime = "text/plain"; break;
default: mime = "application/octet-stream"; break;
}
return mime;
}
private void BigFileWrite(IAsyncResult ar)
{
FileStream fs = (FileStream)ar.AsyncState;
fs.EndWrite(ar);
fs.Flush();
fs.Close();
}
}
}

参考文章：http://blog.ncmem.com/wordpress/2023/12/07/net%e6%96%87%e4%bb%b6%e4%b8%8a%e4%bc%a0%e5%92%8c%e4%b8%8b%e8%bd%bd/

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