Question

我尝试使用blob colomun将文件上传到表中。它有效，但不正确，可以帮助吗？此代码上传，但不正确。当我打开表格时，我看到了| ID = 1 | File_Z=COM.ibm.db2.jdbc.app.DB2Blob@54c6c724 |

FileStream stream = new FileStream(textBox4.Text, FileMode.Open, FileAccess.Read);
            BinaryReader reader = new BinaryReader(stream);
            byte[] file = reader.ReadBytes((int)stream.Length);

            reader.Close();
            stream.Close();
            string query = "UPDATE UPDATE_Z SET FILE_Z=? WHERE ID='"+1+"';";

            {
                OleDbConnection connection = new OleDbConnection(conn);
                connection.Open();
                OleDbCommand command = connection.CreateCommand();
                // command.CreateParameter();

                command.CommandText = query;

                command.Parameters.Add("FILE_Z", OleDbType.Binary, file.Length);
                command.Parameters[0].Value = file;
                command.ExecuteNonQuery();
                connection.Close();
               // for (int i=0; i < file.Length;i++ )
                //{
                  // MessageBox.Show(file[i].ToString());
                //}

            }
            query = "SELECT FILE_Z FROM UPDATE_Z where ID ='"+1+"'";
            FileStream stream1;
            BinaryWriter writer;

            int bufferSize = 100;
            byte[] outByte = new byte[bufferSize];

            long retval;
            long startIndex = 0;

            string pubID = "";


            OleDbConnection connection1 = new OleDbConnection(conn);
            connection1.Open();
            OleDbCommand command1 = connection1.CreateCommand();
            command1.CommandText = query;
            OleDbDataReader reader1 = command1.ExecuteReader(System.Data.CommandBehavior.Default);



            while (reader1.Read())
            {
             //   pubID = reader1.GetString(0);

                stream1 = new FileStream("version1.txt", FileMode.OpenOrCreate, FileAccess.Write);
                writer = new BinaryWriter(stream1);
                startIndex = 0;
               retval = reader1.GetBytes(0, startIndex, outByte, 0, bufferSize);

                while (retval == bufferSize)
                {
                    writer.Write(outByte);
                    writer.Flush();
                    startIndex += bufferSize;
                    retval = reader1.GetBytes(0, startIndex, outByte, 0, bufferSize);
                }
                writer.Write(outByte, 0, (int)retval - 1);
                writer.Flush();

                writer.Close();

                stream1.Close();
            }

            reader1.Close();
            connection1.Close();

输出文件“ZAP.EXE”大小为0 kb，但字节数组文件不为空....

Answer 1

此代码适用于我：

FileStream stream = new FileStream(textBox4.Text, FileMode.Open, FileAccess.Read);
            BinaryReader reader = new BinaryReader(stream);
            byte[] file = reader.ReadBytes((int)stream.Length);

            reader.Close();
            stream.Close();
            string query = "UPDATE UPDATE_Z SET FILE_Z=? WHERE ID='"+1+"';";

            {
                OleDbConnection connection = new OleDbConnection(conn);
                connection.Open();
                OleDbCommand command = connection.CreateCommand();
                // command.CreateParameter();

                command.CommandText = query;

                command.Parameters.Add("FILE_Z", OleDbType.Binary, file.Length);
                command.Parameters[0].Value = file;
                command.ExecuteNonQuery();
                connection.Close();
               // for (int i=0; i < file.Length;i++ )
                //{
                  // MessageBox.Show(file[i].ToString());
                //}

            }
            query = "SELECT FILE_Z FROM UPDATE_Z where ID ='"+1+"'";
            FileStream stream1;
            BinaryWriter writer;

            int bufferSize = 100;
            byte[] outByte = new byte[bufferSize];

            long retval;
            long startIndex = 0;

            string pubID = "";


            OleDbConnection connection1 = new OleDbConnection(conn);
            connection1.Open();
            OleDbCommand command1 = connection1.CreateCommand();
            command1.CommandText = query;
            OleDbDataReader reader1 = command1.ExecuteReader(System.Data.CommandBehavior.Default);



            while (reader1.Read())
            {
             //   pubID = reader1.GetString(0);

                stream1 = new FileStream("version1.txt", FileMode.OpenOrCreate, FileAccess.Write);
                writer = new BinaryWriter(stream1);
                startIndex = 0;
               retval = reader1.GetBytes(0, startIndex, outByte, 0, bufferSize);

                while (retval == bufferSize)
                {
                    writer.Write(outByte);
                    writer.Flush();
                    startIndex += bufferSize;
                    retval = reader1.GetBytes(0, startIndex, outByte, 0, bufferSize);
                }
                writer.Write(outByte, 0, (int)retval);
                writer.Flush();

                writer.Close();

                stream1.Close();
            }

            reader1.Close();
            connection1.Close();

问题在于此代码writer.Write(outByte, 0, (int)retval - 1); 丢失了文件和文件中的最后一个字节未满，我不知道这行代码需要什么......

Db2 blob上传文件

1 个答案: