文件读写锁

避免文件被死锁，lock 确保当一个线程位于代码的临界区时，另一个线程不进入临界区。如果其他线程试图进入锁定的代码，则它将一直等待（即被阻止），直到该对象被释放。
下面是一个文件的锁工厂：

    /// <summary>
    /// 文件锁工厂
    /// </summary>
    public class LockFactory
    {
        public object lockObj = new object();

        private LockFactory()
        {
            
        }

        private static LockFactory _lockFactory = new LockFactory();
        public static LockFactory Instance
        {
            get
            {
                return _lockFactory;
            }
        }

        private IDictionary<string, object> lockDictionary = new Dictionary<string, object>();

        public object GetLock(string filename)
        {
            lock (lockObj)
            {
                if (lockDictionary.ContainsKey(filename))
                {
                    return lockDictionary[filename];
                }
                else
                {
                    var obj = new object();
                    lockDictionary[filename] = obj;
                    return obj;
                }
            }
        }
    }

一般在文件的写，往文件里面追加，删除文件，创建文件，读取文件等等中文件最好是加一下锁。。。

 public class IOLock
    {
        public static void FileWrite(string filename,string content)
        {
            lock (LockFactory.Instance.GetLock(filename))
            {
                File.WriteAllText(filename, content);
            }
        }

        public static void FileAppend(string filename, string content)
        {
            lock (LockFactory.Instance.GetLock(filename))
            {
                File.AppendAllText(filename, content);
            }
        }

        public static void DeleteFile(string filename)
        {
            lock (LockFactory.Instance.GetLock(filename))
            {
                File.Delete(filename);
            }
        }

        public static void CreateFile(string filename)
        {
            lock (LockFactory.Instance.GetLock(filename))
            {
                File.Create(filename).Close();
            }
        }

        public static void CreateFileText(string filename)
        {
            lock (LockFactory.Instance.GetLock(filename))
            {
                File.CreateText(filename).Close();
            }
        }

        public static string ReadFileText(string filename)
        {
            lock (LockFactory.Instance.GetLock(filename))
            {
                return File.ReadAllText(filename);
            }
        }
    }

 同一时间只让一个线程访问资源，其他线程等待！