private void operateFlatFile()
{
string path;
FileStream fs;
byte[] _read, _write;
int start, end;
start = 0;
end = 50;
// read
path = Server.MapPath("http://www.cnblogs.com/document/encode.txt");
fs = new FileStream(path, FileMode.Open);
_read = new byte[end];
fs.Read(_read, start, end);
fs.Close();
// print
Encoding ur = Encoding.GetEncoding("gb2312");
string content = ur.GetString(_read);
Response.Write(content + "<br>");
// write
path = Server.MapPath("http://www.cnblogs.com/document/new.txt");
fs = new FileStream(path, FileMode.OpenOrCreate) ;
Encoding uw = Encoding.GetEncoding("utf-8") ;
_write = uw.GetBytes(content);
fs.Write(_write, start, _write.Length);
fs.Close();
// show message
Response.Write( "succ.");
}