今天想写个jdbc连接mysql的测试，写好了以后连不上msql,报如下错误：

com.mysql.jdbc.CommunicationsException: Communications link failure

Last packet sent to the server was 0 ms ago.

at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1070)

at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2120)

at com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:723)

at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:298)

at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:282)

at java.sql.DriverManager.getConnection(DriverManager.java:525)

at java.sql.DriverManager.getConnection(DriverManager.java:171)

at welfare.DBUtil.getMySQLConnection(DBUtil.java:64)

at welfare.Test.main(Test.java:17)

Caused by: com.mysql.jdbc.CommunicationsException: Communications link failure

Last packet sent to the server was 0 ms ago.

at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1070)

at com.mysql.jdbc.MysqlIO.(MysqlIO.java:335)

at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2043)

... 7 more

Caused by: java.net.ConnectException: Connection refused: connect

at java.net.PlainSocketImpl.socketConnect(Native Method)

at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)

at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)

at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)

at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)

at java.net.Socket.connect(Socket.java:520)

at java.net.Socket.connect(Socket.java:470)

at java.net.Socket.(Socket.java:367)

at java.net.Socket.(Socket.java:209)

at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:253)

at com.mysql.jdbc.MysqlIO.(MysqlIO.java:284)

... 8 more

后来仔细一检查才发现原来是url连接的端口写错了。