c# redis 利用锁（StackExchange.Redis LockTake）来保证数据在高并发情况下的正确性

之前有写过一篇介绍c#操作redis的文章 http://www.cnblogs.com/axel10/p/8459434.html ，这篇文章中的案例使用了StringIncrement来实现了高并发情况下key值的稳定增加，但如果要用锁的方式而不是StringIncrement方法，那该怎么做呢？

LockTake涉及到三个参数：key,token和TimeSpan，分别表示redis数据库中该锁的名称、锁的持有者标识和有效时间。下面将用一个多线程增加key值的案例来演示LockTake/LockRelease的用法。

using StackExchange.Redis;
using StackExchange.Redis.Extensions.Core;
using StackExchange.Redis.Extensions.Core.Configuration;
using StackExchange.Redis.Extensions.Newtonsoft;
using System;
using System.Threading;

namespace RedisTest
{
class Program
{
static RedisValue Token = Environment.MachineName;
static RedisKey Key = "lock";

static void Ins()
{
Thread thread = new Thread(() =>
{
for (int i = 0; i < 100; i++)
{

if (client.Database.LockTake(Key, Token, TimeSpan.MaxValue))   //key表示的是redis数据库中该锁的名称，不可重复。 Token用来标识谁拥有该锁并用来释放锁。TimeSpan表示该锁的有效时间。
{
try
{
int key = client.Get<int>("key");

client.Add("key", key + 10);
}
catch (Exception e)
{
Console.WriteLine(e);
throw;
}
finally
{
client.Database.LockRelease(Key, Token);
}
}
else
{
Console.WriteLine("locking");
while (!TryAgain(10))
{
Thread.Sleep(1);
}
}
}
});
thread.Start();
}

private static StackExchangeRedisCacheClient client;

static void Main(string[] args)
{
var redisConfiguration = new RedisConfiguration() //配置
{
Hosts = new RedisHost[]
{
new RedisHost() {Host = "127.0.0.1", Port = 6379}
}
};

client = new StackExchangeRedisCacheClient(new NewtonsoftSerializer(), redisConfiguration);
client.Add("key", 0);

for (int j = 0; j < 10; j++)
{
Ins();
}

Thread.Sleep(2000);

int i = client.Get<int>("key");
Console.WriteLine(i);
Console.ReadKey();
}

static bool TryAgain(int value)
{
if (client.Database.LockTake(Key, Token, TimeSpan.MaxValue))
{
try
{
int key = client.Get<int>("key");

client.Add("key", key + value);
}
catch (Exception e)
{
Console.WriteLine(e);
throw;
}
finally
{
client.Database.LockRelease(Key, Token);
}

return true;
}
else
{
return false;
}
}
}
}