启动、运行都完全没问题，但是与 Tomcat 6 不同的是，停止的时候出现两个严重的错误：
严重: The web application  registered the JBDC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
严重: The web application  appears to have started a TimerThread named [MySQL Statement Cancellation Timer] via the java.util.Timer API but has failed to stop it. To prevent a memory leak, the timer (and hence the associated thread) has been forcibly canceled.
第一个错误是说 MySQL 的驱动必须手工的进行注销，第二个错误是 MySQL 的驱动里有个线程无法停止。
不过是在停止 Tomcat 才出的错，无所谓了。