@staticmethod
def get_join_fields(qs):
    """
        获得进行查询的model对象的join对象字段
        :return:
        """
    join_model_fields = {}
    for join_models in qs._joins.values():
        for jm in join_models:
            dest_meta = jm.dest._meta
            dest_name = dest_meta.name
            for f in dest_meta.sorted_fields:
                join_model_fields['%s.%s' % (dest_name, f.name)] = f
    return join_model_fields
