我认为您应该将请求而不是URL传递给session.dataTask

I think you should pass your request instead of the url to session.dataTask

我的代码如下：

private let url = URL(string: "http://example.com/")!

func httpPost(jsonData: Data) {
    if !jsonData.isEmpty {
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
        request.httpBody = jsonData

        URLSession.shared.getAllTasks { (openTasks: [URLSessionTask]) in
            NSLog("open tasks: \(openTasks)")
        }

        let task = URLSession.shared.dataTask(with: request, completionHandler: { (responseData: Data?, response: URLResponse?, error: Error?) in
            NSLog("\(response)")
        })
        task.resume()
    }
}