Question

我正在阅读输出到textview的1-5mb日志文件，并搜索输出到另一个textview的特定行。目前只需1分钟即可获得1mb文件。有没有人知道除了我正在使用的方法之外的任何更快的搜索线或字符串的方法？

Imports EnterpriseDT.Net.Ftp

Public Class Form1

Private Sub SettingsToolStripMenuItem_Click(sender As System.Object, e As System.EventArgs) Handles SettingsToolStripMenuItem.Click

End Sub

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
    Dim sw As New Stopwatch
    Dim FullLine As String = ""
    Dim ScriptLine As String = ""
    sw.Start()

    Dim ll As New Queue(Of String)

    Dim i As String = ""

    Using TestFile As New IO.StreamReader("c:\test.txt", System.Text.Encoding.Default, False, 4096)

        Using OutFile As New IO.StreamWriter("c:\SBOutFile.txt", False, System.Text.Encoding.Default, 4096)

            While TestFile.EndOfStream = False

                i = TestFile.ReadLine

                If i.Contains(".sqf") And i.Contains("handleGear.sqf") = False Then
                    ScriptLine = ScriptLine & i & vbNewLine & vbNewLine
                    FullLine = FullLine & i & vbNewLine & vbNewLine
                Else
                    FullLine = FullLine & i & vbNewLine & vbNewLine
                End If

            End While

        End Using

    End Using

    sw.Stop()
    TextBox1.Text = FullLine
    TextBox2.Text = ScriptLine
    RichTextBox1.AppendText(String.Format("Run_Queue took {0} Milliseconds." & Environment.NewLine, sw.ElapsedMilliseconds))
End Sub

Private Sub Button1_Click_1(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    Try
        'connect to ftp server
        Dim ftp As New FTPConnection
        ftp.ServerAddress = "-"
        ftp.ServerPort = "-"
        ftp.UserName = "-"
        ftp.Password = "-"
        ftp.Connect()
        ftp.ChangeWorkingDirectory("-")
        ftp.TransferType = FTPTransferType.BINARY

        'download a file
        ftp.DownloadFile("c:\test.txt", "scripts.log")

        'ftp.RenameFile("scripts.log", "scripts_test.log")

        'close the connection
        ftp.Close()

    Catch ex As Exception
        MessageBox.Show(ex.Message.ToString())
    End Try
End Sub

Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click

End Sub

结束班

Answer 1

鉴于您在阅读时正在进行大量阅读和连接，我怀疑其部分时间/性能问题。我可能会考虑将ScriptLine和FullLine的声明从String类型更改为StringBuilder，因为Strings在技术上是不可变的。这意味着每个连接实际上都被拆除了前一个对象，并在其位置创建了一个新对象。 StringBuilders专为重型串联场景而设计。循环结束后，您可以将其转换回String。

此外，编译的正则表达式搜索速度可能比String.Contains快。您的正则表达式字符串将类似于“（？！handleGear）.sqf”，意思是“在字符串”.sqf“前面找到除”handleGear“之外的任何零个或多个字符序列。

我没有机会测试那个表达式，所以提供了这个警告。如果我有机会参加考试，我很乐意修改并告知你。

祝你好运！

Answer 2

我只是想发布我最终提出的内容。这是对我所拥有的一个非常大的改进。

'Read file
    Dim sw As New Stopwatch
    Dim FullLine As String = ""
    Dim ScriptLine As String = ""
    sw.Start()

    Dim ll As New Queue(Of String)

    Dim i As String = ""
    Dim builder As New StringBuilder
    Using TestFile As New IO.StreamReader("c:\test.txt", System.Text.Encoding.Default, False, 4096)

        builder.AppendLine("Started at: " & DateTime.Now.ToLongTimeString().ToString)
        RichTextBox1.AppendText(Now.ToShortTimeString & " Reading Log File Started" & vbNewLine)
        RichTextBox1.SelectionStart = RichTextBox1.TextLength

        Dim rowCount As Integer = 0

        Do Until TestFile.EndOfStream
            ScriptLine = TestFile.ReadLine
            ScriptLine = LCase(ScriptLine)
            If InStr(ScriptLine, ".sqf") > 0 And InStr(ScriptLine, "handlegear.sqf") < 1 Then 'And InStr(ScriptLine, "createmarkerlocal.sqf") < 1 And InStr(ScriptLine, "setmarkerposlocal.sqf") < 1 
                builder.AppendLine(ScriptLine)
                builder.AppendLine()
            End If
            rowCount = rowCount + 1
        Loop
        builder.AppendLine(Now.ToShortTimeString & "==== Searched " & rowCount & " rows" & vbNewLine)
        builder.AppendLine(Now.ToShortTimeString & " Finished" & vbNewLine)
    End Using

    sw.Stop()

    RichTextBox2.AppendText(builder.ToString & vbNewLine)

    RichTextBox1.AppendText(Now.ToShortTimeString & String.Format(" Run_Queue took {0} Milliseconds." & Environment.NewLine, sw.ElapsedMilliseconds))

vb.net在大型.log文件中搜索特定行

2 个答案: