application/json 不起作用，但 text/json 起作用

Question

在以下代码中，将 ContentType 设置为 application/json 不起作用（服务器发送错误请求），但将其设置为 text/json 可以。为什么？

/*converts form Array to JSON*/
function objectifyForm(formArray) {//serialize data function

  returnArray = {};
  for (var i = 0; i < formArray.length; i++){
    returnArray[formArray[i]['name']] = formArray[i]['value'];
  }
  return returnArray;
}

$(document).ready(function(){
    // click on form submit
    $('#registration-form').on('submit',function(e){
    e.preventDefault();
    var details = JSON.stringify(objectifyForm($(this).serializeArray()));
    console.log(details)
        // send ajax
        $.ajax({
            url: '/newreg', // url where to submit the request
            type : "POST", // type of action POST || GET
            datatype : "json", // data type
            /* this doesn't work*/
            //contentType: "application/json; charset=utf-8",
            /*this does*/
            contentType: "text/json; charset=utf-8",
            data : details,
/*handle success/failure*/
            success : function(result) {},
            error: function(xhr, resp, text) {}
        })
    });
});

Answer 1

Play Framework 后端可能存在错误或未配置的BodyParser。