在VB.net中读取和解析大分隔文本文件

时间:2011-11-23 14:07:06

标签: mysql vb.net visual-studio-2010 data-import

我正在忙于一个应用程序,它读取空间分隔的日志文件,大小从5mb到1gb +,然后将此信息存储到MySQL数据库中,以便以后根据文件中包含的信息打印报告时使用。我试过/找到的方法很有效但很慢。

我做错了吗?还是有更好的方法来处理非常大的文本文件?

我尝试过如下使用textfieldparser:

Using parser As New TextFieldParser("C:\logfiles\testfile.txt")
    parser.TextFieldType = FieldType.Delimited
    parser.CommentTokens = New String() {"#"}
    parser.Delimiters = New String() {" "}
    parser.HasFieldsEnclosedInQuotes = False
    parser.TrimWhiteSpace = True
    While Not parser.EndOfData
        Dim input As String() = parser.ReadFields()
        If input.Length = 10 Then
            'add this to a datatable
        End If
    End While
End Using

这适用于较大的文件但速度很慢。

然后尝试使用OleDB连接到文本文件,按照以下函数结合我事先写入目录的schema.ini文件:

Function GetSquidData(ByVal logfile_path As String) As System.Data.DataTable
    Dim myData As New DataSet
    Dim strFilePath As String = ""
    If logfile_path.EndsWith("\") Then
        strFilePath = logfile_path
    Else
        strFilePath = logfile_path & "\"
    End If
    Dim mySelectQry As String = "SELECT * FROM testfile.txt WHERE Client_IP <> """""
    Dim myConnection As New System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & strFilePath & ";Extended Properties=""text;HDR=NO;""")
        Dim dsCmd As New System.Data.OleDb.OleDbDataAdapter(mySelectQry, myConnection)
        dsCmd.Fill(myData, "logdata")
        If Not myConnection.State = ConnectionState.Closed Then
            myConnection.Close()
        End If
    Return myData.Tables("logdata")
End Function

schema.ini文件:

[testfile.txt]
Format=Delimited( )
ColNameHeader=False
Col1=Timestamp text
Col2=Elapsed text
Col3=Client_IP text
Col4=Action_Code text
Col5=Size double
Col6=Method text
Col7=URI text
Col8=Ident text
Col9=Hierarchy_From text
Col10=Content text

任何人都有任何想法如何更快地阅读这些文件?

CNC中 更正了上面代码中的拼写错误

2 个答案:

答案 0 :(得分:2)

那里有两个可能很慢的操作:

  • 文件阅读
  • 将大量数据插入db

将它们分开并测试花费最多时间。即编写一个简单读取文件的测试程序,以及另一个只插入大量记录的测试程序。看哪一个是最慢的。

一个问题可能是您正在将整个文件读入内存?

尝试使用Stream逐行阅读。这是code example copied from MSDN

Imports System
Imports System.IO

Class Test
    Public Shared Sub Main()
        Try
            ' Create an instance of StreamReader to read from a file.
            ' The using statement also closes the StreamReader.
            Using sr As New StreamReader("TestFile.txt")
                Dim line As String
                ' Read and display lines from the file until the end of
                ' the file is reached.
                Do
                    line = sr.ReadLine()
                    If Not (line Is Nothing) Then
                        Console.WriteLine(line)
                    End If
                Loop Until line Is Nothing
            End Using
        Catch e As Exception
            ' Let the user know what went wrong.
            Console.WriteLine("The file could not be read:")
            Console.WriteLine(e.Message)
        End Try
    End Sub
End Class

答案 1 :(得分:-2)

从我的头脑中说,尝试实施某种线程来分散工作量。