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 stroke_rectangle(self, x, y, w, h):
		self.line(x,y,w,True)
		self.line(x,y+h-1,w,True)
		self.line(x,y,h,False)
		self.line(x+w-1,y,h,False)