tomcat sprngmvc druid 连接mysql 问题，求大神帮忙看看

[csdn_peter]

数据库连接：driverClassName=com.mysql.cj.jdbc.Driver
mysql版本：5.7
jdk：1.8

问题描述：隔一段时间就会报异常如下异常，但系统能使用；tomcat停了发布系统后就起动不了了

2018-05-02 22:13:47.19 | create connection SQLException,
url: jdbc:mysql://172.30.18.236:3306/bd_mes?serverTimezone=Hongkong&useUnicode=true&characterEncoding=utf8&useSSL=false&autoReconnect=true&useServerPrepStmts=true, errorCode 0, state 08001

java.sql.SQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:108)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:95)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:87)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:61)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:71)
at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:932)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:857)
at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:444)
at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:230)
at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:226)
at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:149)
at com.alibaba.druid.filter.stat.StatFilter.connection_connect(StatFilter.java:218)
at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:143)
at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1515)
at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1578)
at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:2466)
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:59)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:103)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:149)
at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:165)
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:92)
at com.mysql.cj.NativeSession.connect(NativeSession.java:152)
at com.mysql.cj.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:876)
... 10 more
Caused by: java.net.SocketException: No buffer space available (maximum connections reached?): connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:173)
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:66)
... 12 more

[csdn_peter]

没有人吗...