本人做一个JavaWeb小项目，数据库连接正常，数据也可以读取出来，但数据死活写不进数据库

貌似是tomcat的问题，研究三四天了，快奔溃了，大神们帮帮忙，十分感谢!
信息: Reloading Context with name [/nwnuSecondHandWeb] has started
十一月 02, 2016 8:23:05 下午 org.apache.catalina.loader.WebappClassLoaderBase clearReferencesJdbc
警告: The web application [nwnuSecondHandWeb] 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.
十一月 02, 2016 8:23:05 下午 org.apache.catalina.loader.WebappClassLoaderBase clearReferencesThreads
警告: The web application [nwnuSecondHandWeb] appears to have started a thread named [MySQL Statement Cancellation Timer] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
java.lang.Object.wait(Native Method)
java.lang.Object.wait(Object.java:502)
java.util.TimerThread.mainLoop(Timer.java:526)
java.util.TimerThread.run(Timer.java:505)

JDBC驱动没有安装好？

存的SQL语句对吗？

你的插入语句对么？你这样描述，，，把你查询和插入数据库的部分代码都贴出来，看下。