开发环境里，在vmware的nat模式下装了一个mysql 5.5.22 ，从主机程序访问数据库总是提示：
cannot establish a connection to jdbc:mysql://192.168.80.131:3306/manager using com.mysql.jdbc.Driver
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.
...connection refused.
找来找去，不是因为jdbc驱动的问题，也不是因为虚拟机防火墙开着的问题，也不是mysql访问账户的问题，而因为：
/etc/mysql/my.cnf里 bind-address的问题，修改为具体的IP地址，或者注释掉即可：
如下：
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
#bind-address = 127.0.0.1
#
#bind-address = 192.168.80.131
默认是127，可以屏蔽其他网络ip访问数据库，只能本地访问，确实是很安全。:)
参考链接：http://stackoverflow.com/questions/10567064/why-i-get-this-error-communicationslinkfailure-thelastpacketsent-when