6

我有一个简单的静态日志记录类。但是，它绝对不是线程安全的，因为每个调用都试图写入同一个文件。我得到这些例外：

The process cannot access the file 'logfile.txt' because it is being used by another process.
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath) 
...

使其线程安全的最佳方法是什么？

public static class Logger
{
    private static readonly string LOG_FILENAME = "logfile.txt";
    private static readonly string LOG_FOLDER = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "App name");
    private static readonly string LOG_FULLPATH = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "App name", LOG_FILENAME);

    public static void LogMessageToFile(string msg)
    {
        msg = string.Format("{0:G}: {1}{2}", DateTime.Now, msg, Environment.NewLine);
        File.AppendAllText(LOG_FULLPATH, msg);
    }
}

作为一个日志功能，我希望能够从我的代码的许多不同部分访问它（因此，为什么我选择它是静态的）。但是，我想为了使它成为线程安全的，我总是必须将一个公共对象传递给 lock() on，我认为这违背了静态函数的目的。或者事实并非如此？

4

2 回答 2

22 
public static class Logger
{
    private static readonly string LOG_FILENAME = "logfile.txt";
    private static readonly string LOG_FOLDER = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "App name");
    private static readonly string LOG_FULLPATH = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "App name", LOG_FILENAME);

    private static Object theLock=new Object();

    public static void LogMessageToFile(string msg)
    {
        msg = string.Format("{0:G}: {1}{2}", DateTime.Now, msg, Environment.NewLine);
        lock (theLock)
        {
            File.AppendAllText(LOG_FULLPATH, msg);
        }
    }
}
于 2013-05-14T00:33:41.323 回答
2

在您的 LogMessageToFile 方法中，您需要一个锁来防止多线程访问：

private static Object _mylock = new Object();
public static void LogMessageToFile(string msg)
{
    lock(_mylock)
    {
       msg = string.Format("{0:G}: {1}{2}", DateTime.Now, msg, Environment.NewLine);
       File.AppendAllText(LOG_FULLPATH, msg);
    }
}
于 2013-05-14T00:33:05.727 回答