#贴下源码，这样其他人才可以帮你分析一下
一般造成这个异常的情况有很多种，下面就简单的提示一些，希望对你有帮助。
- IP address or hostname in JDBC URL is wrong.
- Hostname in JDBC URL is not recognized by local DNS server.
- Port number is missing or wrong in JDBC URL.
- DB server is down.
- DB server doesn't accept TCP/IP connections.
- DB server has run out of connections.
- Something in between Java and DB is blocking connections, e.g. a firewall or proxy.
参考文章
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
