怎么样使用HTML5文件域+Filereader分段读取文件并上传到服务器?

怎么样使用HTML5文件域+Filereader分段读取文件并上传到服务器?

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();" />&emsp;
      <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路饭网站的支持!