使用Servlet代码上传Angular js文件

Question

用于与后端Servlet通信的服务。

      $http({
                method: 'POST',
                url: 'http://localhost:8080/Integration/upload',
                headers : {
                    'Content-Type': 'multipart/form-data'
                },
              data:{
                 file:$scope.file
               },


              transformRequest: function (data, headersGetter) {
                  var formData = new FormData();
                  angular.forEach(data, function (value, key) {
                      formData.append(key, value);
                  });

                  var headers = headersGetter();
                  delete headers['Content-Type'];

                  return formData;
              }

        })

我们是否需要自定义指令，并且任何人都可以解释transformrequest方法。预先感谢。

这是我尝试过的servlet代码，但是它不起作用。

            for(FileItem item : multiparts){
                if(!item.isFormField()){
                    String name = new File(item.getName()).getName();
                    item.write( new File(UPLOAD_DIRECTORY + File.separator + name));
                }
            }

           //File uploaded successfully
           request.setAttribute("message", "File Uploaded Successfully");
        } catch (Exception ex) {
           request.setAttribute("message", "File Upload Failed due to " + ex);
        }          

    }else{
        request.setAttribute("message",
                             "Sorry this Servlet only handles file upload request");
    }