下面的错误什么意思呢，还不影响程序的执行，但运行是个严重的提示
The web application [/jsp_servlet_javabean_MVCDemo2]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.
