开发四年只会写业务代码，分布式高并发都不会还做程序员？->>>
错误日志：
ERROR [Druid-ConnectionPool-Create-2015918089] c.a.d.p.DruidDataSource [DruidDataSource.java:1363] create connection error com.mysql.jdbc.exceptions.jdbc4.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 sun.reflect.GeneratedConstructorAccessor54.newInstance(Unknown Source) ~[na:na]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.7.0_45]
at java.lang.reflect.Constructor.newInstance(Constructor.java:526) ~[na:1.7.0_45]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[mysql-connector-java-5.1.27-bin.jar:na]
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121) ~[mysql-connector-java-5.1.27-bin.jar:na]
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:358) ~[mysql-connector-java-5.1.27-bin.jar:na]
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2489) ~[mysql-connector-java-5.1.27-bin.jar:na]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2526) ~[mysql-connector-java-5.1.27-bin.jar:na]
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2311) ~[mysql-connector-java-5.1.27-bin.jar:na]
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834) ~[mysql-connector-java-5.1.27-bin.jar:na]
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) ~[mysql-connector-java-5.1.27-bin.jar:na]
at sun.reflect.GeneratedConstructorAccessor52.newInstance(Unknown Source) ~[na:na]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.7.0_45]
at java.lang.reflect.Constructor.newInstance(Constructor.java:526) ~[na:1.7.0_45]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[mysql-connector-java-5.1.27-bin.jar:na]
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416) ~[mysql-connector-java-5.1.27-bin.jar:na]
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:347) ~[mysql-connector-java-5.1.27-bin.jar:na]
at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1296) ~[druid-0.2.18.jar:0.2.18]
at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1352) ~[druid-0.2.18.jar:0.2.18]
at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:1361) ~[druid-0.2.18.jar:0.2.18]
Caused by: java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:1.7.0_45]
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339) ~[na:1.7.0_45]
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200) ~[na:1.7.0_45]
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182) ~[na:1.7.0_45]
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.7.0_45]
at java.net.Socket.connect(Socket.java:579) ~[na:1.7.0_45]
at java.net.Socket.connect(Socket.java:528) ~[na:1.7.0_45]
at java.net.Socket.<init>(Socket.java:425) ~[na:1.7.0_45]
at java.net.Socket.<init>(Socket.java:241) ~[na:1.7.0_45]
at com.mysql.jdbc.StandardSocketFactory.connect
