C#实现读写分离的五种方法小结

using System.Threading;
 
public class ReadWriteExample
{
    private readonly ReaderWriterLockSlim _lock = new ReaderWriterLockSlim();
    private int _sharedData = 0;
 
    // 读操作
    public int ReadData()
    {
        _lock.EnterReadLock();
        try
        {
            return _sharedData;
        }
        finally
        {
            _lock.ExitReadLock();
        }
    }
 
    // 写操作
    public void WriteData(int value)
    {
        _lock.EnterWriteLock();
        try
        {
            _sharedData = value;
        }
        finally
        {
            _lock.ExitWriteLock();
        }
    }
}

using System.Collections.Concurrent;
 
public class ConcurrentExample
{
    private readonly ConcurrentDictionary<string, int> _data = new();
 
    // 读操作（无锁）
    public int GetValue(string key)
    {
        return _data.TryGetValue(key, out int value) ? value : -1;
    }
 
    // 写操作（内部使用细粒度锁）
    public void UpdateValue(string key, int value)
    {
        _data.AddOrUpdate(key, value, (k, oldValue) => value);
    }
}

public class VolatileExample
{
    private volatile bool _flag = false;
    private int _data = 0;
 
    // 读操作（无锁）
    public int ReadData()
    {
        if (_flag)
            return _data;
        return -1;
    }
 
    // 写操作（需要同步）
    public void WriteData(int value)
    {
        Interlocked.Exchange(ref _data, value); // 原子写入
        Volatile.Write(ref _flag, true);        // 确保写入对其他线程可见
    }
}

public class DatabaseRouter
{
    private static readonly string ReadConnectionString = "Server=ReadServer;...";
    private static readonly string WriteConnectionString = "Server=WriteServer;...";
 
    public IDbConnection GetReadConnection() => 
        new SqlConnection(ReadConnectionString);
 
    public IDbConnection GetWriteConnection() => 
        new SqlConnection(WriteConnectionString);
}
 
// 使用示例
using (var readConn = DatabaseRouter.GetReadConnection())
{
    // 执行查询操作
}
 
using (var writeConn = DatabaseRouter.GetWriteConnection())
{
    // 执行更新操作
}

using System.Collections.Immutable;
 
public class ImmutableExample
{
    private ImmutableList<int> _data = ImmutableList<int>.Empty;
 
    // 读操作（无锁）
    public int GetItem(int index)
    {
        return _data[index];
    }
 
    // 写操作（原子替换）
    public void AddItem(int item)
    {
        ImmutableInterlocked.Update(ref _data, list => list.Add(item));
    }
}