public class Person

     {

         public string Name { get; set; }

         public string Address { get; set; }

         public int Age { get; set; }

     }

 $("#btnJson").on("click", function () {

                 var datajson = { Name: "Jeffcky", Age: 24, Address: "湖南省" };

                 console.log(datajson);

                 $.ajax({

                     url: "../api/WebAPi/PostPerson",

                     contentType: "application/x-www-form-urlencoded;charset=utf-8",

                     dataType: "json",

                     type: "post",

                     data: datajson,

                     success: function (data) {

                         console.log(data);

                     }

                 });

             });

     [HttpPost]

         public IActionResult PostPerson([FromBody]Person p)

         {

             return Json(p);

         }