C#语言的文件下载示例

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Collections;

using System.Net;

using System.IO;

namespace www.xinduofen.com

{

///

/// C#与http服务器端进行对接的工具类

///

classwww.xinduofen.cn

{

///

/// 用于缓存服务器端传输到客户端的SESSIONID或者JSESSIONID

///

private Cookie sessionidCookie = null;

///

/// 从HttpWebServer端获取文件(使用的是"post"方式)

///

/// 请求网址

/// 请求参数集合,无需参数时传入null值

/// 请求cookie集合,无需cookie时传入null值

/// 下载文件将要保存的位置(包括"文件名"."扩展名")

/// 返回true代表成功,false代表失败

public Boolean getFileFromHttpWebServer(String url, Hashtable data, CookieCollection cookies,String fileSaveAddress)

{

Boolean result = false;

if (string.IsNullOrEmpty(url) || string.IsNullOrEmpty(fileSaveAddress))

{

return false;//传入参数异常

}

byte[] data_stream = null;//将要向服务器传输的数据流内容

if (data != null && data.Count > 0)

{

string transportData = "";//将要向服务器传输的字符串内容

foreach (DictionaryEntry de in data)

{

transportData = transportData + de.Key.ToString() + "=" + de.Value.ToString() + "&";//解调出键值对数据

}

transportData = transportData.TrimEnd('&');//去除字符串尾部的 &

if (!string.IsNullOrEmpty(transportData))

{

data_stream = Encoding.UTF8.GetBytes(transportData);//将上传字符串数据打包成数据流

}

}

try

{

HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(url);

//请求方式

req.Method = "POST";

//声明客户端接收任意类型的文件流

req.Accept = "application/octet-stream";

//以键值对形式向服务器传递参数

req.ContentType = "application/x-www-form-urlencoded";

//设置cookie盒子(客户端请求的cookie和服务器端返回的cookie就放在此盒子中)

CookieContainer cookieContainer = new CookieContainer();

if (sessionidCookie != null && !string.IsNullOrEmpty(sessionidCookie.Domain))

{

cookieContainer.Add(sessionidCookie);

}

if (cookies != null)

{

cookieContainer.Add(cookies);//添加调用者传入的cookie集合

}

req.CookieContainer = cookieContainer;

if (data_stream != null && data_stream.Length > 0)

{

//请求数据流的长度

req.ContentLength = data_stream.Length;

using (Stream requestStream = req.GetRequestStream())

{

//写入请求实体流

requestStream.Write(data_stream, 0, data_stream.Length);

}

}

//接收返回值

using (HttpWebResponse myResponse = (HttpWebResponse)req.GetResponse()) {

if (myResponse.Cookies["SESSIONID"] != null)

{

sessionidCookie = myResponse.Cookies["SESSIONID"];

}

else

{

if (myResponse.Cookies["JSESSIONID"] != null)

{

sessionidCookie = myResponse.Cookies["JSESSIONID"];

}

}

////下面为服务器端返回的下载文件名,留下作为参考用的

//if (myResponse.StatusCode == HttpStatusCode.OK)

//{

//    byte[] str = Encoding.GetEncoding("ISO-8859-1").GetBytes(myResponse.GetResponseHeader("Content-Disposition"));

//    string disposition = Encoding.UTF8.GetString(str);

//    Console.WriteLine("disposition:" + disposition);

//}

//流对象使用完后自动关闭

using (Stream stream = myResponse.GetResponseStream())

{

//文件流,流信息读到文件流中,读完关闭

using (FileStream fs = File.Create(fileSaveAddress))

{

//建立字节组,并设置它的大小是多少字节

byte[] bytes = new byte[10240];

int n = -1;

while ((n = stream.Read(bytes, 0, bytes.Length)) > 0)

{

fs.Write(bytes, 0, n); //将指定字节的流信息写入文件流中

}

}

}

}

result = true;//下载成功

}

catch (Exception)

{

Console.WriteLine("请查看传入参数是否正确或者服务器是否关闭");

}

return result;

}

///

/// 获得参数data的消息数据流,以"\r\n"结尾

///

/// 请求参数集合,无需参数时传入null值

/// 消息分隔符

/// 返回参数data的数据流,返回为空代表获得失败

private byte[] getParameterBytes(Hashtable data, String boundary)

{

byte[] parameterBytes = null;

//如果有请求参数

if (data != null && data.Count > 0)

{

string parameterStr = "";

foreach (DictionaryEntry de in data)

{

parameterStr += "--" + boundary;

parameterStr += "\r\n" + "Content-Disposition: form-data;name=\"" + de.Key.ToString() + "\"";

parameterStr += "\r\n" + "Content-Type: text/plain; charset=UTF-8";

parameterStr += "\r\n\r\n" + de.Value.ToString();

parameterStr += "\r\n";

}

if (!string.IsNullOrEmpty(parameterStr))

{

parameterBytes = Encoding.UTF8.GetBytes(parameterStr);//将上传字符串数据打包成数据流

}

}

return parameterBytes;

}

///

/// 获得上传文件的消息头部分字符流,以"\r\n\r\n"结尾

///

/// 上传文件《控件名,上传文件的保存位置(包括"文件名"."扩展名")》

/// 消息分隔符

/// 返回上传文件的消息头部分字符流,返回会为null代表获得失败

private byte[] getUploadFileDeclareBytes(DictionaryEntry de, String boundary)

{

byte[] uploadFileDeclareBytes = null;

//上传文件的消息头描述部分

string uploadFileDeclareStr = "";

uploadFileDeclareStr += "--" + boundary;

uploadFileDeclareStr += "\r\n" + "Content-Disposition: form-data;name=\"" + de.Key.ToString() + "\"; filename=\"" + de.Value.ToString() + "\"";

uploadFileDeclareStr += "\r\n" + "Content-Type: application/octet-stream";

uploadFileDeclareStr += "\r\n\r\n";

if (!string.IsNullOrEmpty(uploadFileDeclareStr))

{

uploadFileDeclareBytes = Encoding.UTF8.GetBytes(uploadFileDeclareStr);//将上传字符串数据打包成数据流

}

return uploadFileDeclareBytes;

}

}

}

内容所有权属于越康体育(专业从事体质测试仪,学生体质测试仪)

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