如何解决？(标签-database|关键词-jdbc)

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException:

Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!

The error may exist in file [D:\ssmbuild-master\Managersystem\out\artifacts\Managersystem_war_exploded\WEB-INF\classes\mapper\UserMapper.xml]

The error may involve com.dao.UserDao.selectByName

The error occurred while executing a query

Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!

org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:96)
org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:441)
com.sun.proxy.$Proxy25.selectOne(Unknown Source)
org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:160)
org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:83)
org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59)
com.sun.proxy.$Proxy27.selectByName(Unknown Source)
com.service.impl.UserService.login(UserService.java:14)
com.controller.UserController.login(UserController.java:26)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:888)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909)
javax.servlet.http.HttpServlet.service(HttpServlet.java:681)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)

</resultMap>
<sql id="Base_Column_List" >
    user_id, password, username
</sql>
<select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select
    <include refid="Base_Column_List" />
    from users
    where user_id = #{user_id,jdbcType=INTEGER}
</select>
<delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    delete from users
    where user_id = #{user_id,jdbcType=INTEGER}
</delete>
<insert id="register" parameterType="com.pojo.User" >
    insert into users(user_id, username, password)
        value (#{user_id}, #{username}, #{password})
</insert>
<update id="updateByPrimaryKeySelective" parameterType="com.pojo.User" >
    update users
    <set >
        <if test="password != null" >
            password = #{password,jdbcType=VARCHAR},
        </if>
        <if test="username != null" >
            username = #{username,jdbcType=VARCHAR},
        </if>
    </set>
    where user_id = #{user_id,jdbcType=INTEGER}
</update>
<update id="updateByPrimaryKey" parameterType="com.pojo.User" >
    update users
    set password = #{password,jdbcType=VARCHAR},
        username = #{username,jdbcType=VARCHAR}
    where user_id = #{user_id,jdbcType=INTEGER}
</update>

<select id="selectByName" resultMap="BaseResultMap" parameterType="com.pojo.User" >
    select
    <include refid="Base_Column_List" />
    from users
    where username = #{username,jdbcType=VARCHAR}
</select>

这是数据库连接出了问题吧 Connections could not be acquired from the underlying databas

在jdbc连接的url后面添加serverTimezone=CST
比如
jdbc:mysql://localhost:3306/test改为
jdbc:mysql://localhost:3306/test?serverTimezone=CST

这是什么鬼

应该是连接的问题，5.1的话是低版本MySQL，
emm据我所知低版本是没有那么多参数的，至少是没有说加时区的，当热可能是我学的不精。
平时用的都是5.7.
我建议是试一试把后面几个参数先去掉试一试，控制变量法。
然后确定一下驱动的版本号是否是5.1的驱动