C#操作本地文件及保存文件到数据库的基本方法总结

using System.IO;

StreamWriter sw=File.CreateText("c://text.txt");  sw.WriteLine("C#");                //写入一行文本 sw.Write("www.csdn.net");             //在文本末尾写入文本 sw.Flush();                    //清空 sw.Close();                    //关闭 

StreamReader sr = File.OpenText("c://text.txt"); sr.ReadLine();                  //读取一行数据 sr.Read();                    //读取一个字符 sr.ReadToEnd();                  //从当前位置读取到文本结束 sr.Close();                    //释放资源 

StreamWriter sw = File.AppendText("c://text.txt"); sw.WriteLine("C#");                 //写入一行文本 sw.Write("www.csdn.net");              //在文本末尾写入文本 sw.Flush();                     //清空 sw.Close();                     //关闭 

File.Exists("c://text.txt"); 

File.Delete("c://text.txt"); 

File.Copy("c://text.txt", "c://copy.txt");   //把c://text.txt复制到c://copy.txt 

File.Copy("c://text.txt", "d://text.txt");  //把c://text.txt移动到d://text.txt 

Directory.Delete("c://test");       //删除C盘下的test文件夹 Directory.CreateDirectory("c://test");  //在C盘创建test文件夹 Directory.Exists("c://test");       //验证C盘test文件夹是否存在 Directory.Move("c://test", "d://test");  //把c:/test移动到d:/test 

create table tb_file (  id       number(20) not null,  file_name    nvarchar2(100),  file_content  blob,  constraint pk_tb_file primary key (id) ) tablespace mydb storage(  initial 64K  minextents 1  maxextents unlimited ); 

create sequence seq_tb_file  --创建自增序列 minvalue 1 maxvalue 9999999999999999999 start with 1 increment by 1 nocache order;  create or replace trigger ai_tb_file --创建触发器，当插入新记录时自增主键id before insert on tb_file for each row when (new.id is null) begin select seq_tb_file.nextval into :new.id from dual; end; 

//添加命名空间 using System; using System.Data.OracleClient; using System.IO; using System.Data;  /// <summary> /// 把文件插入数据库中 /// </summary> /// <param name="filePath">文件名，包含路径，如c:/temp.rar</param> /// <returns></returns> public int Insert(string filePath) {   string connStr = "data source=orcl;user=mydbuser;password=mydbuser;";   OracleConnection conn = new OracleConnection(connStr);   OracleCommand cmd = conn.CreateCommand();    //读取文件   FileStream fs = File.OpenRead(filePath);   byte[] buffer = new byte[fs.Length];   fs.Read(buffer, 0, buffer.Length);    OracleParameter paramFileContent = cmd.CreateParameter();   paramFileContent.OracleType = OracleType.Blob;   paramFileContent.ParameterName = "FileContent";   paramFileContent.Direction = ParameterDirection.Input;   paramFileContent.Value = buffer;   cmd.Parameters.Add(paramFileContent);    OracleParameter paramFileName = cmd.CreateParameter();   paramFileName.OracleType = OracleType.VarChar;   paramFileName.ParameterName = "FileName";   paramFileName.Direction = ParameterDirection.Input;   paramFileName.Value = Path.GetFileName(filePath);   cmd.Parameters.Add(paramFileName);    string sqlInsert = "insert into tb_file (file_name, file_content) values (:FileName, :FileContent)";   cmd.CommandText = sqlInsert;   cmd.CommandType = CommandType.Text;    conn.Open();   int result = cmd.ExecuteNonQuery();   conn.Close();    return result; }   /// <summary> /// 根据文件名从数据库中获取文件 /// </summary> /// <param name="fileName">数据库中的文件名</param> /// <param name="savePath">文件的保存路径，包括文件名，如c:/file.rar</param> public void Select(string fileName, string savePath) {   string connStr = "data source=orcl;user=mydbuser;password=mydbuser;";   OracleConnection conn = new OracleConnection(connStr);   OracleCommand cmd = conn.CreateCommand();    string sqlSelect = "select file_name, file_content from tb_file where file_name=:FileName";   cmd.CommandText = sqlSelect;   cmd.CommandType = CommandType.Text;    OracleParameter paramFileName = cmd.CreateParameter();   paramFileName.OracleType = OracleType.VarChar;   paramFileName.ParameterName = "FileName";   paramFileName.Direction = ParameterDirection.Input;   paramFileName.Value = fileName;   cmd.Parameters.Add(paramFileName);          conn.Open();   OracleDataReader dr = cmd.ExecuteReader();   dr.Read();   byte[] buffer = (byte[])dr["file_content"];   dr.Close();   conn.Close();    //把文件保存到指定路径   File.WriteAllBytes(savePath, buffer); }