时间：2012-08-08
错误表现：重启tomcat时请求连接池超时
错误代码：
INFO: Starting Servlet Engine: Apache Tomcat/6.0.18
2012-08-08 04:06 WARN o.h.u.JDBCExceptionReporter - SQL Error: 0, SQLState: null
2012-08-08 04:06 ERROR o.h.u.JDBCExceptionReporter - An attempt by a client to checkout a Connection has timed out.
2012-08-08 04:06 WARN o.h.c.SettingsFactory - Could not obtain connection metadata
java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
错误代码：
INFO: Starting Servlet Engine: Apache Tomcat/6.0.18
2012-08-08 04:06 WARN o.h.u.JDBCExceptionReporter - SQL Error: 0, SQLState: null
2012-08-08 04:06 ERROR o.h.u.JDBCExceptionReporter - An attempt by a client to checkout a Connection has timed out.
2012-08-08 04:06 WARN o.h.c.SettingsFactory - Could not obtain connection metadata
java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
原因：防火墙数据库的端口关闭