如何在C#中对一个Web服务并行发出多个请求

本文关键字：并行 服务 Web 请求 一个 | 更新日期: 2023-09-27 18:28:45

我需要调用以下3个WCF服务，

var client = new WebClient();
    client.Headers[HttpRequestHeader.ContentType] = "application/json";
    var resultJson1 = client.UploadString("http://localhost:45868/Product/GetAvailableProductsByContact",
                                         jsonser1);
var resultJson2= client.UploadString("http://localhost:45868/Product/GetMemberProductsByContact",
                                         jsonser2);
var resultJson3= client.UploadString("http://localhost:45868/Product/GetCoachProductsByContact",
                                         jsonser3);

这需要花费大量时间才能获得结果并显示在页面上。有人能帮我如何并行执行它们吗？

如何在C#中对一个Web服务并行发出多个请求

您可以使用任务并行库：

Task<string>[] taskArray = new Task<string>[]
    {
        Task.Factory.StartNew(() => {
            var client = new WebClient();
            client.Headers[HttpRequestHeader.ContentType] = "application/json";
            var json = client.UploadString("http://localhost:45868/Product/GetAvailableProductsByContact",
                                     jsonser1);
            return json;
        }),
        Task.Factory.StartNew(() => {
            var client = new WebClient();
            client.Headers[HttpRequestHeader.ContentType] = "application/json";
            var json = client.UploadString("http://localhost:45868/Product/GetMemberProductsByContact",
                                     jsonser2);
            return json;
        }),
        Task.Factory.StartNew(() => {
            var client = new WebClient();
            client.Headers[HttpRequestHeader.ContentType] = "application/json";
            var json = client.UploadString("http://localhost:45868/Product/GetCoachProductsByContact",
                                     jsonser3);
            return json;
        }),
    };
// the request for .Result is blocking and waits until each task
// is completed before continuing; however, they should also all
// run in parallel instead of sequentially.
var resultJson1 = taskArray[0].Result;
var resultJson2 = taskArray[1].Result;
var resultJson3 = taskArray[2].Result;

或者，由于您的请求都非常相似，只是url和上传字符串不同，因此您可以使用LINQ AsParallel数组处理：

var requests = new [] {
    new { Url = "http://localhost:45868/Product/GetAvailableProductsByContact", Input = jsonser1 },
    new { Url = "http://localhost:45868/Product/GetMemberProductsByContact", Input = jsonser2 },
    new { Url = "http://localhost:45868/Product/GetCoachProductsByContact", Input = jsonser3 },
};
var result = requests.AsParallel().Select(req => {
    var client = new WebClient();
    client.Headers[HttpRequestHeader.ContentType] = "application/json";
    var json = client.UploadString(req.Url, req.Input);
    return json;
}).ToArray();
// when above code has finished running, all tasks are completed
var resultJson1 = result[0];
var resultJson2 = result[1];
var resultJson3 = result[2];

您可以使用开始/结束模式：

这个例子展示了如何并行调用两个ws。您可以将此想法扩展到N个服务。

尝试创建一个执行每个调用的Task（MSDN）

你可以尝试做以下

首先为您的每个呼叫创建一个Task<String>

var client = new WebClient();
client.Headers[HttpRequestHeader.ContentType] = "application/json";
Task<String> task1 = Task.Factory.StartNew(() => {
    client.UploadString("http://localhost:45868/Product/GetAvailableProductsByContact",
                                         jsonser1);
});

冲洗并重复其他2个

之后，您可以通过调用task1.Value、task2.Value和task3.Value来加入3个Task<String>的执行，这将返回一个String

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