服务器升级后，数据库无法连接。解决，执行： flash hosts 解决

root@eisc.cn # ./mysqL-h 172.26.230.173 -u root 1  -p 

Enter passw or a: ERROR 1129 (HY 000) :Host‘172.26.36.105'is blocked because of many connection errors; unblock with'mysqLadmin fLush-hosts 

输入passw或a:ERROR 1129（HY 000）：主机“172.26.36.105”由于许多连接错误而被阻止；使用“mysqLadmin刷新主机”解除阻止

com.al id DataSource$Create Connection Thread.run(Druid DataSource .java: 2022) 09-Nov-2021 :22:23.638 WARNING[Localhost-start Stop-1] org.apache.catalina.Loader.Webapp CLassLoader Base.clear References Threads The web application[R0OT] appears to have started a thread named[Druid-Connect ion Pool-D est roy-185119151 ] but has failed to stop it.This is very likely to create a memory Leak.Stacktrace of thread: java.Lang.Thread.sleep(Native Method) com.alibaba.druid.pool.Druid DataSource$Destroy Connection Thread.run(Druid DataSource .java: 2070) 09-Nov-202111:22:23.640WARNING[Localhost-startStop-1]org.apache.catalina.Loader.WebappCLassLoaderBase.cLearReferencesThreadsThewebappLication[ROOT]appearstohavestartedathreadnamed[Druid-Connect ion PooL-Create-887009207] but has fail but has failed to stop it.This is very likely to create a memory leak.Stacktrace of thread: 

 flash hosts                # 执行