我在IntelliJ IDEA 里边运行单个的java类，就可以连接到mysql数据库，但是我编译后放在tomcat下就会出现这个错误，
java.sql.SQLException: Communication failure during handshake. Is there a server
running on localhost:3306?
at org.gjt.mm.mysql.MysqlIO.init(Unknown Source)
at org.gjt.mm.mysql.Connection.connectionInit(Unknown Source)
....
怎么会有这个错误的？
我的mysql明明运行的好好的
------解决方案--------------------
Is there a server
running on localhost:3306?
没看到吗?端口问题!建议把端口改了@