asp.net文件下载[转]
1 public partial class FileDownLoad : System.Web.UI.Page
2 {
3 //提供下载的文件，不编码的话文件名会乱码
4 private string fileName = HttpContext.Current.Server.UrlEncode("规范.rar");
5 private string filePath = HttpContext.Current.Server.MapPath("规范.rar");
6 //使用TransmifFile下载文件
7 protected void btnDL1_Click(object sender, EventArgs e)
8 {
9 FileInfo info = new FileInfo(filePath);
10 long fileSize = info.Length;
11 Response.Clear();
12 Response.ContentType = "application/x-zip-compressed";
13 Response.AddHeader("Content-Disposition", "attachment;filename="+ fileName);
14 //不指明Content-Length用Flush的话不会显示下载进度
15 Response.AddHeader("Content-Length", fileSize.ToString());
16 Response.TransmitFile(filePath, 0, fileSize);
17 Response.Flush();
18 Response.Close();
19 }
20
21 //使用WriteFile下载文件
22 protected void btnDL2_Click(object sender, EventArgs e)
23 {
24 FileInfo info = new FileInfo(filePath);
25 long fileSize = info.Length;
26 Response.Clear();
27 Response.ContentType = "application/octet-stream";
28 Response.AddHeader("Content-Disposition", "attachement;filename=" + fileName);
29 //指定文件大小
30 Response.AddHeader("Content-Length", fileSize.ToString());
31 Response.WriteFile(filePath, 0, fileSize);
32 Response.Flush();
33 Response.Close();
34 }
35
36 //使用OutputStream.Write分块下载文件
37 protected void btnDL3_Click(object sender, EventArgs e)
38 {
39 //指定块大小
40 long chunkSize = 102400;
41 //建立一个100K的缓冲区
42 byte[] buffer = new byte[chunkSize];
43 //已读的字节数
44 long dataToRead = 0;
45 FileStream stream = null;
46 try
47 {
48 //打开文件
49 stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
50 dataToRead = stream.Length;
51
52 //添加Http头
53 Response.ContentType = "application/octet-stream";
54 Response.AddHeader("Content-Disposition", "attachement;filename=" + fileName);
55 Response.AddHeader("Content-Length", dataToRead.ToString());
56
57 while (dataToRead > 0)
58 {
59 if (Response.IsClientConnected)
60 {
61 int length = stream.Read(buffer, 0, Convert.ToInt32(chunkSize));
62 Response.OutputStream.Write(buffer, 0, length);
63 Response.Flush();
64 Response.Clear();
65 dataToRead -= length;
66 }
67 else
68 {
69 //防止client失去连接
70 dataToRead = -1;
71 }
72 }
73 }
74 catch (Exception ex)
75 {
76 Response.Write("Error:" + ex.Message);
77 }
78 finally
79 {
80 if (stream != null)
81 {
82 stream.Close();
83 }
84 Response.Close();
85 }
86 }
87
88 //使用BinaryWrite下载文件，大文件效率不行
89 protected void btnDL4_Click(object sender, EventArgs e)
90 {
91 FileStream stream = null;
92 try
93 {
94 //读文件,大文件一次读入会占用大量内存
95 stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
96 byte[] bytes = new byte[stream.Length];
97 stream.Read(bytes, 0, bytes.Length);
98 stream.Close();
99
100 //添加Http头
101 Response.ContentType = "application/octet-stream";
102 Response.AddHeader("Content-Disposition", "attachement;filename=" + fileName);
103 Response.AddHeader("Content-Length", bytes.Length.ToString());
104 Response.BinaryWrite(bytes);
105 Response.Flush();
106 }
107 catch (Exception ex)
108 {
109 Response.Write("Error:" + ex.Message);
110 }
111 finally
112 {
113 if (stream != null)
114 {
115 stream.Close();
116 }
117 Response.Close();
118 }
119 }
120 //使用BinaryWrite分块下载文件
121 protected void btnDL5_Click(object sender, EventArgs e)
122 {
123 //指定区块和缓冲区
124 long chunkSize = 102400;
125 byte[] buffer = new byte[chunkSize];
126 FileStream stream = null;
127 long dataToRead = 0;
128 try
129 {
130 stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
131 dataToRead = stream.Length;
132 //添加Http头
133 Response.ContentType = "application/octet-stream";
134 Response.AddHeader("Content-Disposition", "attachement;filename=" + fileName);
135 Response.AddHeader("Content-Length", dataToRead.ToString());
136
137 while (dataToRead > 0)
138 {
139 if (Response.IsClientConnected)
140 {
141 int length = stream.Read(buffer, 0, Convert.ToInt32(chunkSize));
142 Response.BinaryWrite(buffer);
143 Response.Flush();
144 Response.Clear();
145
146 dataToRead -= length;
147 }
148 else
149 {
150 dataToRead = -1;
151 }
152 }
153
154 }
155 catch(Exception ex)
156 {
157 Response.Write("Error:" + ex.Message);
158 }
159 finally
160 {
161 if (stream != null)
162 {
163 stream.Close();
164 }
165 Response.Close();
166 }
167 }
168 }
169
以上除了第四种不推荐以外，其他的都可以，但是个人感觉分块下载的要好一点。没有仔细测试，所以可能有问题。
注意：对于中文文件名要编码才能正确显示。对于长中文文件名(UTF8编码后大于153字节的中文)即使编码了，还是有问题的，大家可以参考这个链接。 http://hi.baidu.com/river_5566/blog/item/d66804cef8afb031b700c863.html
转自CSDN博客：http://blog.csdn.net/zabcd117/archive/2009/04/24/4107033.aspx