C# 使用 HttpPost 请求调用 WebService

之前调用 WebService 都是直接添加服务引用，然后调用 WebService 方法的，最近发现还可以使用 Http 请求调用 WebService。这里还想说一句，还是 web api 的调用简单。

WebService 服务端代码：

public class WebServiceDemo : System.Web.Services.WebService
{
    [WebMethod]
    public string HelloWorld()
    {
        return "Hello World";
    }
    [WebMethod]
    public string Sum(string param1, string param2)
    {
        int num1 = Convert.ToInt32(param1);
        int num2 = Convert.ToInt32(param2);
        int sum = num1 + num2;
        return sum.ToString();
    }
}

很简单的代码，只是用于演示。

客户端调用代码：

class Program
{
    static void Main(string[] args)
    {
        Program program = new Program();
        string url = "http://localhost:12544/WebServiceDemo.asmx";
        string method = "Sum";
        string num1 = "1";
        string num2 = "2";
         string result = program.HttpPostWebService(url, method, num1, num2);
        Console.WriteLine(result);
        Console.ReadKey();
    }
    public string HttpPostWebService(string url,string method,string num1,string num2)
    {
        string result = string.Empty;
        string param = string.Empty;
        byte[] bytes = null;
        Stream writer = null;
        HttpWebRequest request = null;
        HttpWebResponse response = null;
        param = HttpUtility.UrlEncode("param1") + "=" + HttpUtility.UrlEncode(num1) + "&" + HttpUtility.UrlEncode("param2") + "=" + HttpUtility.UrlEncode(num2);
        bytes = Encoding.UTF8.GetBytes(param);
        request = (HttpWebRequest)WebRequest.Create(url + "/" + method);
        request.Method = "POST";
        request.ContentType = "application/x-www-form-urlencoded";
        request.ContentLength = bytes.Length;
        try
        {
            writer = request.GetRequestStream();        //获取用于写入请求数据的Stream对象
        }
        catch (Exception ex)
        {
            return "";
        }
        writer.Write(bytes, 0, bytes.Length);       //把参数数据写入请求数据流
        writer.Close();
        try
        {
            response = (HttpWebResponse)request.GetResponse();      //获得响应
        }
        catch (WebException ex)
        {
            return "";
        }
        #region 这种方式读取到的是一个返回的结果字符串
        Stream stream = response.GetResponseStream();        //获取响应流
        XmlTextReader Reader = new XmlTextReader(stream);
        Reader.MoveToContent();
        result = Reader.ReadInnerXml();
        #endregion
        #region 这种方式读取到的是一个Xml格式的字符串
        //StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
        //result = reader.ReadToEnd();
        #endregion 
        response.Dispose();
        response.Close();
        //reader.Close();
        //reader.Dispose();
        Reader.Dispose();
        Reader.Close();
        stream.Dispose();
        stream.Close();
        return result;
    }
}

第一种读取方式的返回结果：

第二种读取方式的返回结果：

PS：如果遇到调用时报错，可以尝试在服务端（即WebService）的 web.config 配置中添加如下配置节点。

　<system.web>
    <webServices>
      <protocols>
        <add name="HttpPost" />
      </protocols>
    </webServices>
  </system.web>