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 _load_data(self, directory):
        try:
            with open(directory, 'r') as f:
                data = f.read()
                return literal_eval(data)
        except OSError as e:
            raise