将查询字符串，转换成字典
    a=123&b=456
    {'a': '123', 'b': '456'}
    :param query_str:
    :return:

def query_str_2_dict(query_str):
    """
    将查询字符串，转换成字典
    a=123&b=456
    {'a': '123', 'b': '456'}
    :param query_str:
    :return:
    """
    if query_str:
        query_list = query_str.split('&')
        query_dict = {}
        for t in query_list:
            x = t.split('=')
            query_dict[x[0]] = x[1]
    else:
        query_dict = {}
    return query_dict