C# HttpClient调用接口

///
/// 基于.net4.5 HttpClient实现
/// 由于HttpClient有预热机制，第一次进行访问时比较慢，所以最好不用用到HttpClient就New一次，应该使用单例模式保持一个对象即可
///
public class WebAPIHelper where Output:class
{
private static WebAPIHelper _webApi;

	private WebAPIHelper() { }

	public WebAPIHelper<Output> Instance
	{
		get
		{
			if(_webApi==null)
			{
				_webApi = new WebAPIHelper<Output>();
			}
			return _webApi;
		}
	}

	/// <summary>
	/// Get请求调用
	/// </summary>
	/// <param name="urlPath"></param>
	/// <returns></returns>
	public async Task<Output> GetCall(string urlPath)
	{
		HttpClientHandler handler = new HttpClientHandler() {AutomaticDecompression=DecompressionMethods.GZip };
		HttpClient httpClient = new HttpClient();
		//异步请求
		HttpResponseMessage response = await httpClient.GetAsync(urlPath);
		//确保响应正常，如果响应不正常，则抛出异常
		response.EnsureSuccessStatusCode();
		//异步读取数据
		string resultStr = await response.Content.ReadAsStringAsync();
		Output result = JsonConvert.DeserializeObject<Output>(resultStr);
		return result;
	}

	/// <summary>
	/// Post请求调用
	/// </summary>
	/// <param name="urlPath"></param>
	/// <param name="data">post数据</param>
	/// <returns></returns>
	public async Task<Output> PostCall(string urlPath,string data)
	{
		HttpClientHandler handler = new HttpClientHandler() { AutomaticDecompression = DecompressionMethods.GZip };
		HttpClient httpClient = new HttpClient(handler);
		//HttpContent是HTTP实体正文和内容标头的基类。
		HttpContent httpContent = new StringContent(data, Encoding.UTF8, "text/json");
		//httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("BasicAuth", Ticket);//验证请求头赋值
		//httpContent.Headers.Add(string name,string value) //添加自定义请求头

		//发送异步Post请求
		HttpResponseMessage response = await httpClient.PostAsync(urlPath, httpContent);
		response.EnsureSuccessStatusCode();
		string resultStr = await response.Content.ReadAsStringAsync();
		Output result = JsonConvert.DeserializeObject<Output>(resultStr);
		return result;
	}
}