从数据库保存Blob文件存储到本地，via C#

public static void saveSrc(string curDate)
{
MySql.Data.MySqlClient.MySqlConnection conn = new MySql.Data.MySqlClient.MySqlConnection();

string connStr = "server=" + Form1.dbIp + ";user id=" + Form1.dbUser + ";password=" + Form1.dbPasswd + ";database=" + Form1.dbName + ";pooling=false;charset=utf8";

conn.ConnectionString = connStr;

try
{
conn.Open();
}

catch
{
MessageBox.Show("Database Connection Error");
return;
}

MySql.Data.MySqlClient.MySqlCommand cmd = new MySql.Data.MySqlClient.MySqlCommand();
cmd.Connection = conn;

cmd.CommandText = "select srcfile from t_calpuf_conf where identifier=\""+identifier+"\"";

System.Data.Common.DbDataReader reader = cmd.ExecuteReader();

byte[] buffer = null;

if (reader.HasRows)
{

reader.Read();
long len = reader.GetBytes(0, 0, null, 0, 0);//0是 因为只选出一个字段  第一个0
buffer = new byte[len];

// 字节数
len = reader.GetBytes(0, 0, buffer, 0, (int)len);

// 先得创建保存文件的目录

System.IO.DirectoryInfo di = new System.IO.DirectoryInfo(srcDir + "\\" + identifier);
di.Create();

// 再保存

string savePath = srcDir + "\\"+identifier+"\\src" + curDate + ".src";
BinaryWriter bw = new BinaryWriter(File.Open(savePath, FileMode.OpenOrCreate));
bw.Write(buffer);
bw.Close();
}

cmd.Dispose();
conn.Close();
}