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我试图限制我必须连接到端点的最大连接数，我通过设置 ServicePointManager.DefaultConnectionLimit 来做到这一点，但它不起作用。为了测试这一点，我设置了一个休眠 5 秒然后返回的端点。

这是我的代码：

class Program
{
    private static Uri uri = new Uri("http://myservice.com?sleepForMillisecond=5000"));

    static void Main(string[] args)
    {
        ServicePointManager.DefaultConnectionLimit = 1;
        MainAsync().Wait();
    }

    static async Task MainAsync()
    {
        var watch = Stopwatch.StartNew();
        var tasks = new List<Task>()
            {
                Task.Run(async () => await MakeCallWithHttpClient()),
                Task.Run(async () => await MakeCallWithHttpClient()),
                Task.Run(async () => await MakeCallWithHttpClient())
            };

        await Task.WhenAll(tasks);
        watch.Stop();
        Console.WriteLine("Elapsed Time For HttpClient: " + watch.Elapsed);

        watch.Restart();
        tasks = new List<Task>()
            {
                Task.Run(async () => await MakeCallWithWebClient()),
                Task.Run(async () => await MakeCallWithWebClient()),
                Task.Run(async () => await MakeCallWithWebClient())
            };

        await Task.WhenAll(tasks);
        watch.Stop();
        Console.WriteLine("Elapsed Time For WebClient: " + watch.Elapsed);
        Console.WriteLine("Press Enter To Exit.");
        Console.ReadLine();
    }

    private static async Task MakeCallWithHttpClient()
    {
        var client = new HttpClient();
        await client.GetStringAsync(uri);
        Console.WriteLine("Done");
    }

    private static async Task MakeCallWithWebClient()
    {
        var client = new WebClient();
        await client.DownloadStringTaskAsync(uri);
        Console.WriteLine("Done");
    }
}

下面是输出：

Done
Done
Done
Elapsed Time For HttpClient: 00:00:05.0953943
Done
Done
Done
Elapsed Time For WebClient: 00:00:15.0450096

如您所见，异步 HttpClient 不受最大连接数 1 的限制，因为并行进行 3 个调用需要 5 秒，而异步 WebClient 受 1 个连接限制，因为并行进行 3 个调用需要 15 秒。

我的问题是......如何使用异步 HttpClient 限制最大连接数？

谢谢。

4

1 回答 1

0

对所有请求使用相同的 HttpClient 实例，连接限制将按预期工作。

于 2014-08-02T14:45:45.397 回答