从SQL Server存储过程调用Web服务

Question

我曾使用此查询在本地系统中调用Web服务..我收到响应为＆＃34; NULL＆＃34;

网络服务工作正常....

  DECLARE @obj INT
  DECLARE @sUrl VARCHAR(200)
  DECLARE @response VARCHAR(8000)

  SET @sUrl = 'http://localhost/MyWorks/SampleWebService.asmx/HelloWorld'
  EXEC sp_OACreate 'MSXML2.ServerXMLHttp', @obj OUT
  EXEC sp_OAMethod @obj,'Open',NULL,'GET',@sUrl,false
  EXEC sp_OAMethod @obj,'send'
  EXEC sp_OAGetProperty @obj,'responseText',@response OUT
  SELECT @response [response]
  EXEC sp_OADestroy @obj

网络服务代码：

 public class SampleWebService : System.Web.Services.WebService
 {    
        [WebMethod]
        public string HelloWorld()
        {
            string conString = ConfigurationManager.ConnectionStrings["rajeevConnectionString"].ConnectionString;
            using (SqlConnection con = new SqlConnection(conString))
            {
                SqlCommand cmd = new SqlCommand("update Employees set FirstName = 'Jhon' where ID=7", con);
                con.Open();
                cmd.ExecuteNonQuery();
                con.Close();
            }
            return "Updated";
            //sending the mail code.
        }
    }