连接mysql出错

mysql version: 5.5.40 mysql community server

不论是从图形界面软件还是java通过jdbc连接，始终提示出错：

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.GeneratedConstructorAccessor13.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1127)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:356)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2502)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2539)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2321)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:832)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
    at sun.reflect.GeneratedConstructorAccessor10.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:417)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
    at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:146)
    at com.alibaba.druid.filter.stat.StatFilter.connection_connect(StatFilter.java:211)
    at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:140)
    at com.alibaba.druid.filter.stat.StatFilter.connection_connect(StatFilter.java:211)
    at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:140)
    at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1355)
    at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1409)
    at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:1649)
Caused by: java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:579)
    at java.net.Socket.connect(Socket.java:528)
    at java.net.Socket.<init>(Socket.java:425)
    at java.net.Socket.<init>(Socket.java:241)
    at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:258)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:306)
    ... 19 more
2015-01-07 20:25:20,333 ERROR [com.alibaba.druid.pool.DruidDataSource] - <create connection error>
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

解决方式：

运行C:\Program Files\MySQL\MySQL Server 5.5\bin下的MySQLInstanceConfig.exe。重新进行mysql实例配置

重新配置后ok