Asp.Net Core2.1前后使用HttpClient的两种方式

//do something...
using (var httpClient = new HttpClient())
{
 var requestUri = "http://aspcore.online/api/resource/getresource";
 var httpResponseMessage = await httpClient.GetAsync(requestUri);
 //do something...

 return Ok(httpResponseMessage);
}

//do something...
using (var httpClient = new HttpClient())
{
 var requestUri = "http://aspcore.online/api/resource/postresource";
 var httpResponseMessage = await httpClient.PostAsJsonAsync(requestUri,"星城软件");
 //do something...

 return Ok(httpResponseMessage);
}

private static HttpClient _httpClient = null;
public HttpClient CreateHttpClient()
{
 if (_httpClient == null) _httpClient = new HttpClient();
 return _httpClient;
}

//在startup中完成单例注入
services.AddSingleton<IHttpClient, StandardHttpClient>();

public interface IHttpClient
{
 //do something
}

public class StandardHttpClient : IHttpClient
{
 private HttpClient _client;

 public StandardHttpClient()
 {
 _client = new HttpClient();
 }

 //do something...
}

 services.AddHttpClient();

[Route("api/[controller]")]
[ApiController]
public class HttpClientController : ControllerBase
{
 IHttpClientFactory _httpClientFactory;

 public HttpClientController(IHttpClientFactory httpClientFactory)
 {
 _httpClientFactory = httpClientFactory;
 }

 [HttpGet]
 [Route(nameof(Index))]
 public async Task<IActionResult> Index()
 {
 var client = _httpClientFactory.CreateClient();
 var result = await client.GetAsync("http://aspcore.online/api/resource/getresource");
 return Ok(result);
 }
}