按照教程写的，启动一个小时不到，老是报错 Communications link failure。mysql用的8点几的。

com.mysql.cj.jdbc.exceptions.CommunicationsException: 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 com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:172)
	at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:862)
	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:1470)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1533)
	at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:2333)
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.1.5</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.11</version>
    </dependency>

网上答案貌似都不行