ssm 使用中的一些问题

1.问题：[org.mybatis.spring.SqlSessionUtils] - Creating a new SqlSession 
[org.mybatis.spring.SqlSessionUtils] - SqlSession[org.apache.ibatis.session.defaults.DefaultSqlSession@1a714e6e] was not registered for synchronization because synchronization is not active 
[org.springframework.jdbc.datasource.DataSourceUtils] - Fetching JDBC Connection from DataSource 
[org.mybatis.spring.transaction.SpringManagedTransaction] - JDBC Connection [jdbc: mysql://localhost:3306/iot, UserName=root@localhost, MySQL Connector Java]* will not be managed by Spring*
[com.haoyifen.mySSMTemplate.dao.UserMapper.selectByPrimaryKey] - ==> Preparing: select ID, USER_ID, USER_NAME, SEX, ADDRESS, PHONE_NUMBER, MAIL_BOX from user where ID = ? 
[com.haoyifen.mySSMTemplate.dao.UserMapper.selectByPrimaryKey] - ==> Parameters: 1(Integer) 
[com.haoyifen.mySSMTemplate.dao.UserMapper.selectByPrimaryKey] - <== Total: 1 
[org.mybatis.spring.SqlSessionUtils] - Closing non transactional SqlSession[org.apache.ibatis.session.defaults.DefaultSqlSession@1a714e6e]

原因:重复扫描事务配置所致，spring-mybatis中扫描了一遍service

<context:component-scan base-package="cn.yzh" >

　　<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller" />

</context:component-scan>

spring-mvc中又扫描了一遍

<context:component-scan base-package="cn.yzh" >

spring如果要使事务生效，就需要cglib为userService生成代理子类，在spring.xml中已经生成了代理类，而在spring-mvc.xml中，又重新扫描了一遍，使得原先cglib生成的代理子类失效，从而事务拦截也失效。

解决:

于是在spring-mvc中改成<context:component-scan base-package="cn.yzh.controller" > 只让它扫描controller，而spring-mybatis不扫描controller就好了

参考:https://blog.csdn.net/haoyifen/article/details/51172647

2.报错：

java.lang.AbstractMethodError: Method com/mchange/v2/c3p0/impl/NewProxyPreparedStatement.isClosed()
解决：在pom中更新c3p0 jar包版本

3.

java.sql.SQLException: The server time zone value '???ú±ê×??±??' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.

解决：jdbc中加上&serverTimezone=UTC，以此来解决乱码问题