def insertDomain(self, domain, indegree=0, outdegree=0):
		'''增加一个域名'''
		cur = self.conn.cursor()
		cur.execute("INSERT INTO Domains VALUES (NULL,?,?,?)", (domain, indegree, outdegree))
		# 写入到文件中
		self.conn.commit()
def encode(self):
        return {"rx_sw_if_index": self._rx_index,
                "tx_sw_if_index": self._tx_index, "nh": self._nh_addr}