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 __init__(self):
                self.stride = (4, 8, 16, 32, 64)
                self.short = (200, 100, 50, 25, 13)
                self.long = (334, 167, 84, 42, 21)