angularjs中$http异步上传Excel文件方法

<form id="fileForm" enctype="multipart/form-data"> <button id="import_asset" type="button" ng-click="import_asset()">上传文件</button> <input id="file_asset" type="file" style="display: none;"/></form>

$scope.import_asset = function () { $("#file_asset").click();};$("#file_asset").on("change", function(){ var formData = new FormData(); var file = document.getElementById("file_asset").files[0]; if(file.name){  var fileName = file.name.substring(file.name.lastIndexOf(".") + 1);  if(fileName =="xlsx" || fileName =="xls"){   formData.append('file', file);   $http({    method:"post",    url:commonService.projectName + "/so/assetmanage/upload",    data:formData,    headers : {     'Content-Type' : undefined    },    transformRequest : angular.identity   }).then(function (response) {    if(response.status == 200){     alert("文件上传成功！！！");    }else{     alert("文件上传失败！！！");    }   });  }else{   alert("文件格式不正确，请上传以.xlsx，.xls 为后缀名的文件。");   $("#file_asset").val("");  } }});