def updateInfo(self, item, newlinks, oldlinks):
		'''爬虫爬完之后对数据库内容进行更新'''
		cur = self.conn.cursor()
		cur.execute("SELECT wid,did FROM Websites WHERE url=?", (item['url'],))
		wid, did = cur.fetchone()
		# website记录更新
		cur.execute("UPDATE Websites SET title=?,visited=1 WHERE wid=?", (item['title'], wid,))
		# 对应的domain记录中出度也需要更新
		cur.execute("UPDATE Domains SET outdegree=outdegree+? WHERE did=?", (len(item['links']), did,))

		# 对该网页中所有链接涉及的记录进行更新
		# 外部判断未出现过的链接
		for link,domain in newlinks:
			self.insertWebsite(link, domain)

		# 外部判断出现过的链接
		for link,domain in oldlinks:
			# 对对应的domain记录入度增加
			cur.execute("UPDATE Domains SET outdegree=outdegree+1 WHERE domain=?", (domain,))
		# 写入到文件
		self.conn.commit()
def _handle_signal_gracefully(cls, signum, signame, traceback_lines):
        """Signal handler for non-fatal signals which raises or logs an error and exits with
        failure."""
        # Extract the stack, and format an entry to be written to the exception log.
        formatted_traceback = cls._format_traceback(
            traceback_lines=traceback_lines, should_print_backtrace=True
        )
        signal_error_log_entry = cls._CATCHABLE_SIGNAL_ERROR_LOG_FORMAT.format(
            signum=signum, signame=signame, formatted_traceback=formatted_traceback
        )
        # TODO: determine the appropriate signal-safe behavior here (to avoid writing to our file
        # descriptors re-entrantly, which raises an IOError).
        # This method catches any exceptions raised within it.
        cls.log_exception(signal_error_log_entry)

        # Create a potentially-abbreviated traceback for the terminal or other interactive stream.
        formatted_traceback_for_terminal = cls._format_traceback(
            traceback_lines=traceback_lines,
            should_print_backtrace=cls._should_print_backtrace_to_terminal,
        )
        terminal_log_entry = cls._CATCHABLE_SIGNAL_ERROR_LOG_FORMAT.format(
            signum=signum, signame=signame, formatted_traceback=formatted_traceback_for_terminal
        )
        # Exit, printing the output to the terminal.
        cls._exit_with_failure(terminal_log_entry)