1.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.
原因:Mybatis3.2 没有DAO接口,有DAO类和Mapper文件,DAO类需加@Repository注解
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException:Column 'release_time' in order clause is ambigous
原因:一般发生在多表连接查询,不知道列release_time是哪个表的列,ambigous:模棱两可