LogStore.CreateLogArchiveSnapshot 方法

参考

定义

命名空间:: System.IO.Log

程序集:: System.IO.Log.dll

重要

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拍摄制作备份所需的日志存储区状态的快照。

重载

CreateLogArchiveSnapshot()	拍摄日志存储区状态的快照，以制作备份。
CreateLogArchiveSnapshot(SequenceNumber, SequenceNumber)	拍摄指定序列号之间的日志存储区状态的快照，以制作备份。

CreateLogArchiveSnapshot()

拍摄日志存储区状态的快照，以制作备份。

public:
 System::IO::Log::LogArchiveSnapshot ^ CreateLogArchiveSnapshot();

public System.IO.Log.LogArchiveSnapshot CreateLogArchiveSnapshot ();

member this.CreateLogArchiveSnapshot : unit -> System.IO.Log.LogArchiveSnapshot

Public Function CreateLogArchiveSnapshot () As LogArchiveSnapshot

LogArchiveSnapshot

一个包含制作存档所需状态的 LogArchiveSnapshot 对象。

例外

NotSupportedException

日志存储区不可存档。

ObjectDisposedException

该方法是在序列已释放之后调用的。

IOException

创建存档快照时发生 I/O 错误。

ArgumentException

自变量无效。

InvalidOperationException

执行了无效的操作。

OutOfMemoryException

没有足够的内存来继续执行程序。

SequenceFullException

记录序列已满。

UnauthorizedAccessException

操作系统拒绝了对指定的日志存储区的访问。

示例

下面的示例演示如何将 LogStore 存档到 XML 文档。

class LogBackup
{
    static void ArchiveToXML(LogStore logStore, string fileName)
    {
        LogArchiveSnapshot snapshot = logStore.CreateLogArchiveSnapshot();

        XmlTextWriter writer = new XmlTextWriter(fileName, Encoding.ASCII);

        writer.WriteStartElement("logArchive");
        foreach(FileRegion region in snapshot.ArchiveRegions)
        {
            writer.WriteStartElement("fileRegion");
            writer.WriteElementString("path", region.Path);
            writer.WriteElementString("length", region.FileLength.ToString());
            writer.WriteElementString("offset", region.Offset.ToString());
            using(Stream dataStream = region.GetStream())
            {
                byte[] data = new byte[dataStream.Length];
                dataStream.Read(data, 0, data.Length);
                writer.WriteElementString("data", Convert.ToBase64String(data));
            }
            writer.WriteEndElement();
        }
        writer.WriteEndElement();
        writer.Close();
        logStore.SetArchiveTail(snapshot.LastSequenceNumber);
    }
    static void RestoreFromXML(string fileName)
    {
        using(XmlTextReader reader = new XmlTextReader(fileName))
        {
            reader.ReadStartElement("logArchive");
            while(reader.IsStartElement())
            {
                string path = reader.ReadElementString("path");
                long length = Int64.Parse(reader.ReadElementString("length"));
                long offset = Int64.Parse(reader.ReadElementString("offset"));
                string dataString = reader.ReadElementString("data");
                byte[] data = Convert.FromBase64String(dataString);
                FileStream fileStream;
                using(fileStream = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write))
                {
                    fileStream.SetLength(length);
                    fileStream.Position = offset; fileStream.Write(data, 0, data.Length);
                }
            }
        reader.ReadEndElement();
        }
    }
}

Friend Class LogBackup
    Private Shared Sub ArchiveToXML(ByVal logStore As LogStore, ByVal fileName As String)
        Dim snapshot As LogArchiveSnapshot = logStore.CreateLogArchiveSnapshot()

        Dim writer As New XmlTextWriter(fileName, Encoding.ASCII)

        writer.WriteStartElement("logArchive")
        For Each region As FileRegion In snapshot.ArchiveRegions
            writer.WriteStartElement("fileRegion")
            writer.WriteElementString("path", region.Path)
            writer.WriteElementString("length", region.FileLength.ToString())
            writer.WriteElementString("offset", region.Offset.ToString())
            Using dataStream As Stream = region.GetStream()
                Dim data(dataStream.Length - 1) As Byte
                dataStream.Read(data, 0, data.Length)
                writer.WriteElementString("data", Convert.ToBase64String(data))
            End Using
            writer.WriteEndElement()
        Next region
        writer.WriteEndElement()
        writer.Close()
        logStore.SetArchiveTail(snapshot.LastSequenceNumber)

    End Sub
    Private Shared Sub RestoreFromXML(ByVal fileName As String)
        Using reader As New XmlTextReader(fileName)
            reader.ReadStartElement("logArchive")
            Do While reader.IsStartElement()
                Dim path = reader.ReadElementString("path")
                Dim length = Int64.Parse(reader.ReadElementString("length"))
                Dim offset = Int64.Parse(reader.ReadElementString("offset"))
                Dim dataString = reader.ReadElementString("data")
                Dim data() = Convert.FromBase64String(dataString)
                Dim fileStream As FileStream
                fileStream = New FileStream(path, FileMode.OpenOrCreate, FileAccess.Write)
                Using fileStream
                    fileStream.SetLength(length)
                    fileStream.Position = offset
                    fileStream.Write(data, 0, data.Length)
                End Using
            Loop
            reader.ReadEndElement()
        End Using
    End Sub
End Class

适用于

CreateLogArchiveSnapshot(SequenceNumber, SequenceNumber)

拍摄指定序列号之间的日志存储区状态的快照，以制作备份。

public:
 System::IO::Log::LogArchiveSnapshot ^ CreateLogArchiveSnapshot(System::IO::Log::SequenceNumber first, System::IO::Log::SequenceNumber last);

public System.IO.Log.LogArchiveSnapshot CreateLogArchiveSnapshot (System.IO.Log.SequenceNumber first, System.IO.Log.SequenceNumber last);

member this.CreateLogArchiveSnapshot : System.IO.Log.SequenceNumber * System.IO.Log.SequenceNumber -> System.IO.Log.LogArchiveSnapshot

Public Function CreateLogArchiveSnapshot (first As SequenceNumber, last As SequenceNumber) As LogArchiveSnapshot

参数

first: SequenceNumber

要存档的范围中的起始序列号。

last: SequenceNumber

要存档的范围中的结束序列号。