mysql升级至8后，数据库用户名、密码、权限都正确，依然连接不上
错误如下：
Caused by: java.lang.RuntimeException: java.sql.SQLException: Connections could not be acquired from the underlying database! at com.github.pagehelper.PageHelper.getUrl(PageHelper.java:287) at com.github.pagehelper.PageHelper.getSqlUtil(PageHelper.java:310) at com.github.pagehelper.PageHelper.initSqlUtil(PageHelper.java:266) at com.github.pagehelper.PageHelper.intercept(PageHelper.java:253) at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:60) at com.sun.proxy.$Proxy48.query(Unknown Source) at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:108) ... 63 more Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database! at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:118) at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:692) at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:140) at com.github.pagehelper.PageHelper.getUrl(PageHelper.java:284) ... 69 more Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source. at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1469) at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:644) at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:554) at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutAndMarkConnectionInUse(C3P0PooledConnectionPool.java:758) at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:685) ... 71 more
解决办法
第一步：升级jdk为1.8
第二步：升级mysql驱动
<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.11</version> </dependency>
第三步：更新jdbc.driverClassName和jdbc.url
jdbc.driverClassName=com.mysql.cj.jdbc.Driver jdbc.url=jdbc:mysql://127.0.0.1:3306/db_sms?useSSL=false&characterEncoding=utf8&allowMultiQueries=true