Could not create connection to database server

启动项目报错，报错如下：就是连接mysql的时候报的错

2018-07-24 17:01:13,368 ERROR [com.alibaba.druid.pool.DruidDataSource] - create connection error, url: jdbc:mysql://127.0.0.1:3306/demo?useUnicode=true&characterEncoding=utf-8&useSSL=false, errorCode 0, state 08001
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.
	at sun.reflect.GeneratedConstructorAccessor19.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
	at com.mysql.jdbc.Util.getInstance(Util.java:383)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1023)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:997)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:983)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:928)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2576)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2309)
	at com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:834)
	at com.mysql.jdbc.JDBC4Connection.(JDBC4Connection.java:46)
	at sun.reflect.GeneratedConstructorAccessor16.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:419)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:148)
	at com.alibaba.druid.filter.stat.StatFilter.connection_connect(StatFilter.java:211)
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:142)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1410)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1464)
	at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:1969)
Caused by: java.lang.NullPointerException
	at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:3299)
	at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1967)
	at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1893)
	at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1287)
	at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2494)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2527)
	... 15 more

 

 

此时用的

     com.alibaba
     druid
     1.0.18


   mysql
   mysql-connector-java
   5.1.30
   runtime

升级这2个jar，升级到如下配置即可

     com.alibaba
     druid
     1.1.0


   mysql
   mysql-connector-java
   5.1.4
   runtime