说明：使用Ajax方式上传，文件不能过大，最好小于三四百兆，因为过多的连续Ajax请求会使后台崩溃，获取InputStream中数据会为空，尤其在Google浏览器测试过程中。
1.简单分段读取文件为Blob，ajax上传到服务器
<div class=container> <div class=panel panel-default> <div class=panel-heading>分段读取文件：</div> <div class=panel-body> <input type=file id=file /> <blockquote style=word-break:break-all;></blockquote> </div> </div></div>
JS：
/** 分段读取文件为blob ，并使用ajax上传到服务器* 分段上传exe文件会抛出异常*/var fileBox = document.getElementById('file');file.onchange = function () { //获取文件对象 var file = this.files[0]; var reader = new FileReader(); var step = 1024 * 1024; var total = file.size; var cuLoaded = 0; console.info(文件大小： + file.size); var startTime = new Date(); //读取一段成功 reader.onload = function (e) { //处理读取的结果 var loaded = e.loaded; //将分段数据上传到服务器 uploadFile(reader.result, cuLoaded, function () { console.info('loaded:' + cuLoaded + 'current:' + loaded); //如果没有读完，继续 cuLoaded += loaded; if (cuLoaded < total) { readBlob(cuLoaded); } else { console.log('总共用时：' + (new Date().getTime() - startTime.getTime()) / 1000); cuLoaded = total; } }); } //指定开始位置，分块读取文件 function readBlob(start) { //指定开始位置和结束位置读取文件 //console.info('start:' + start); var blob = file.slice(start, start + step); reader.readAsArrayBuffer(blob); } //开始读取 readBlob(0); //关键代码上传到服务器 function uploadFile(result, startIndex, onSuccess) { var blob = new Blob([result]); //提交到服务器 var fd = new FormData(); fd.append('file', blob); fd.append('filename', file.name); fd.append('loaded', startIndex); var xhr = new XMLHttpRequest(); xhr.open('post', '../ashx/upload2.ashx', true); xhr.onreadystatechange = function () { if (xhr.readyState == 4 && xhr.status == 200) { // var data = eval('(' + xhr.responseText + ')'); console.info(xhr.responseText); if (onSuccess) onSuccess(); } } //开始发送 xhr.send(fd); }}后台代码：
/// <summary>/// upload2 的摘要说明/// </summary>public class upload2 : IHttpHandler{ LogHelper.LogHelper _log = new LogHelper.LogHelper(); int totalCount = 0; public void ProcessRequest(HttpContext context) { HttpContext _Context = context; //接收文件 HttpRequest req = _Context.Request; if (req.Files.Count <= 0) { WriteStr(获取服务器上传文件失败); return; } HttpPostedFile _file = req.Files[0]; //获取参数 // string ext = req.Form[extention]; string filename = req.Form[filename]; //如果是int 类型当文件大的时候会出问题 最大也就是 1.9999999990686774G int loaded = Convert.ToInt32(req.Form[loaded]); totalCount += loaded; string newname = @F:/JavaScript_Solution/H5Solition/H5Solition/Content/TempFile/; newname += filename; //接收二级制数据并保存 Stream stream = _file.InputStream; if (stream.Length <= 0) throw new Exception(接收的数据不能为空); byte[] dataOne = new byte[stream.Length]; stream.Read(dataOne, 0, dataOne.Length); FileStream fs = new FileStream(newname, FileMode.Append, FileAccess.Write, FileShare.Read, 1024); try { fs.Write(dataOne, 0, dataOne.Length); } finally { fs.Close(); stream.Close(); } _log.WriteLine((totalCount + dataOne.Length).ToString()); WriteStr(分段数据保存成功); } private void WriteStr(string str) { HttpContext.Current.Response.Write(str); } public bool IsReusable { get { return true; } }2.分段读取文件为blob ，并使用ajax上传到服务器，追加中止、继续功能操作
<div class=container> <div class=panel panel-default> <div class=panel-heading>分段读取文件：</div> <div class=panel-body> <input type=file id=file /> <br /> <input type=button value=中止 onclick=stop(); />  <input type=button value=继续 onclick=containue(); /> <br /> <progress id=progressOne max=100 value=0 style=width:400px;></progress> <blockquote id=Status style=word-break:break-all;></blockquote> </div> </div></div>
JS:
/** 分段读取文件为blob ，并使用ajax上传到服务器* 使用Ajax方式提交上传数据文件大小应该有限值，最好500MB以内* 原因短时间过多的ajax请求，Asp.Net后台会崩溃获取上传的分块数据为空* 取代方式，长连接或WebSocket*/var fileBox = document.getElementById('file');var reader = null; //读取操作对象var step = 1024 * 1024 * 3.5; //每次读取文件大小var cuLoaded = 0; //当前已经读取总数var file = null; //当前读取的文件对象var enableRead = true;//标识是否可以读取文件fileBox.onchange = function () { //获取文件对象 file = this.files[0]; var total = file.size; console.info(文件大小： + file.size); var startTime = new Date(); reader = new FileReader(); //读取一段成功 reader.onload = function (e) { //处理读取的结果 var result = reader.result; var loaded = e.loaded; if (enableRead == false) return false; //将分段数据上传到服务器 uploadFile(result, cuLoaded, function () { console.info('loaded:' + cuLoaded + '----current:' + loaded); //如果没有读完，继续 cuLoaded += loaded; if (cuLoaded < total) { readBlob(cuLoaded); } else { console.log('总共用时：' + (new Date().getTime() - startTime.getTime()) / 1000); cuLoaded = total; } //显示结果进度 var percent = (cuLoaded / total) * 100; document.getElementById('Status').innerText = percent; document.getElementById('progressOne').value = percent; }); } //开始读取 readBlob(0); //关键代码上传到服务器 function uploadFile(result, startIndex, onSuccess) { var blob = new Blob([result]); //提交到服务器 var fd = new FormData(); fd.append('file', blob); fd.append('filename', file.name); fd.append('loaded', startIndex); var xhr = new XMLHttpRequest(); xhr.open('post', '../ashx/upload2.ashx', true); xhr.onreadystatechange = function () { if (xhr.readyState == 4 && xhr.status == 200) { if (onSuccess) onSuccess(); } else if (xhr.status == 500) { //console.info('请求出错，' + xhr.responseText); setTimeout(function () { containue(); }, 1000); } } //开始发送 xhr.send(fd); }}//指定开始位置，分块读取文件function readBlob(start) { //指定开始位置和结束位置读取文件 var blob = file.slice(start, start + step); reader.readAsArrayBuffer(blob);}//中止function stop() { //中止读取操作 console.info('中止，cuLoaded：' + cuLoaded); enableRead = false; reader.abort();}//继续function containue() { console.info('继续，cuLoaded：' + cuLoaded); enableRead = true; readBlob(cuLoaded);}后台代码同上
3.分段读取文件为二进制数组 ，并使用ajax上传到服务器
使用二进制数组传递的方式，效率特别低，最终文件还与原始大小有些偏差
HTML内容同上
JS：
/* * 分段读取文件为二进制数组 ，并使用ajax上传到服务器 * 使用二进制数组传递的方式，效率特别低，最终文件还与原始大小有些偏差 */var fileBox = document.getElementById('file');var reader = new FileReader(); //读取操作对象var step = 1024 * 1024; //每次读取文件大小var cuLoaded = 0; //当前已经读取总数var file = null; //当前读取的文件对象var enableRead = true;//标识是否可以读取文件fileBox.onchange = function () { //获取文件对象 if (file == null) //如果赋值多次会有丢失数据的可能 file = this.files[0]; var total = file.size; console.info(文件大小： + file.size); var startTime = new Date(); //读取一段成功 reader.onload = function (e) { //处理读取的结果 var result = reader.result; var loaded = e.loaded; if (enableRead == false) return false; //将分段数据上传到服务器 uploadFile(result, cuLoaded, function () { console.info('loaded:' + cuLoaded + '----current:' + loaded); //如果没有读完，继续 cuLoaded += loaded; if (cuLoaded < total) { readBlob(cuLoaded); } else { console.log('总共用时：' + (new Date().getTime() - startTime.getTime()) / 1000); cuLoaded = total; } //显示结果进度 var percent = (cuLoaded / total) * 100; document.getElementById('Status').innerText = percent; document.getElementById('progressOne').value = percent; }); } //开始读取 readBlob(0); //关键代码上传到服务器 function uploadFile(result, startIndex, onSuccess) { var array = new Int8Array(result); console.info(array.byteLength); //提交到服务器 var fd = new FormData(); fd.append('file', array); fd.append('filename', file.name); fd.append('loaded', startIndex); var xhr = new XMLHttpRequest(); xhr.open('post', '../ashx/upload3.ashx', true); xhr.onreadystatechange = function () { if (xhr.readyState == 4 && xhr.status == 200) { // console.info(xhr.responseText); if (onSuccess) onSuccess(); } else if (xhr.status == 500) { console.info('服务器出错'); reader.abort(); } } //开始发送 xhr.send(fd); }}//指定开始位置，分块读取文件function readBlob(start) { //指定开始位置和结束位置读取文件 var blob = file.slice(start, start + step); reader.readAsArrayBuffer(blob);}//中止function stop() { //中止读取操作 console.info('中止，cuLoaded：' + cuLoaded); enableRead = false; reader.abort();}//继续function containue() { console.info('继续，cuLoaded：' + cuLoaded); enableRead = true; readBlob(cuLoaded);}后台代码：
/// <summary>/// upload3 的摘要说明/// </summary>public class upload3 : IHttpHandler{ LogHelper.LogHelper _log = new LogHelper.LogHelper(); int totalCount = 0; public void ProcessRequest(HttpContext context) { HttpContext _Context = context; //接收文件 HttpRequest req = _Context.Request; string data = req.Form[file]; //转换方式一 //int[] intData = data.Split(',').Select(q => Convert.ToInt32(q)).ToArray(); //byte[] dataArray = intData.ToList().ConvertAll(x=>(byte)x).ToArray(); //转换方式二 byte[] dataArray = data.Split(',').Select(q => int.Parse(q)).Select(q => (byte)q).ToArray(); //获取参数 string filename = req.Form[filename]; //如果是int 类型当文件大的时候会出问题 最大也就是 1.9999999990686774G int loaded = Convert.ToInt32(req.Form[loaded]); totalCount += loaded; string newname = @F:/JavaScript_Solution/H5Solition/H5Solition/Content/TempFile/; newname += filename; try { // 接收二级制数据并保存 byte[] dataOne = dataArray; FileStream fs = new FileStream(newname, FileMode.Append, FileAccess.Write, FileShare.Read, 1024); try { fs.Write(dataOne, 0, dataOne.Length); } finally { fs.Close(); } _log.WriteLine((totalCount + dataOne.Length).ToString()); WriteStr(分段数据保存成功); } catch (Exception ex) { throw ex; } } private void WriteStr(string str) { HttpContext.Current.Response.Write(str); } public bool IsReusable { get { return false; } }}总结以上所述是小编给大家介绍的HTML5 文件域+FileReader 分段读取文件并上传到服务器，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对VeVb武林网网站的支持！