tomcat启动，报问题：To prevent a memory leak, the JDBC Driver has been forcibly unregistered.

Tomcat启动时出现一下问题：

严重: Error listenerStart
2014-4-21 16:10:35 org.apache.catalina.core.StandardContext startInternal
严重: Context [/hn] startup failed due to previous errors
2014-4-21 16:10:35 org.apache.catalina.core.ApplicationContext log
信息: Closing Spring root WebApplicationContext
2014-4-21 16:10:35 org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
严重: The web application [/hn] registered the JDBC driver [com.alibaba.druid.proxy.DruidDriver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
2014-4-21 16:10:35 org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
严重: The web application [/hn] registered the JDBC 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.
2014-4-21 16:10:35 org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
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经过排查，是tomcat server.xml的配置参数deployOnStartup设置有问题，将deployOnStartup="true"改成deployOnStartup="false"，以上问题就不再出现。