我有这样一个来自Facebook的参数： {"object":"page","entry":[{"id":"xxxxxxxx","time":1542363897584,"messaging":[{"sender":{"id":"xxxxxxxx"},"recipient":{"id":"xxxxxxxxx"},"timestamp":1542363897166,"message":{"mid":"OBhuHFel0lF_GFyp6kyHryjVQbb61lOQl3sqOSZcLpQhcO37Lx6NSp2tKg6pdz_Zd22EQOwBqftDtH2Au40ECw","seq":142884,"text":"xxxxxxxxxxx"}}]}],"dc_action":"xxxxxxxx"} . 请告诉我从上面获取线程ID的方法 .