Question

急救急救！我在myeclipse中连接数据库是老是报Communications link failure due to underlying exception:

Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection ("jdbc:mysql://localhost:3306/testuseUnicode=true&characterEncoding=utf8","root","1234");

报以下错误
com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:

** BEGIN NESTED EXCEPTION **

java.net.SocketException
MESSAGE: java.net.ConnectException: Connection refused: connect

STACKTRACE:

java.net.SocketException: java.net.ConnectException: Connection refused: connect
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:151)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:280)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:1765)
at com.mysql.jdbc.Connection.<init>(Connection.java:430)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:268)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at util.DBUtil.getConnection(DBUtil.java:13)
at util.DBUtil.main(DBUtil.java:37)

** END NESTED EXCEPTION **

-----conn-----------null
at com.mysql.jdbc.Connection.createNewIO(Connection.java:1830)
at com.mysql.jdbc.Connection.<init>(Connection.java:430)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:268)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at util.DBUtil.getConnection(DBUtil.java:13)
at util.DBUtil.main(DBUtil.java:37)

Answer 1

是不是防火墙屏蔽了相关通信进程了？
是不是配置写错了，比如帐号密码、数据库连接字符串等等的
到这里找找看吧 http://xidige.com

Answer 2

暂时发现了一个错误：
("jdbc:mysql://localhost:3306/testuseUnicode=true&characterEncoding=utf8","root","1234");
少个问号——>
("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8","root","1234");

Answer 3

你确定你数据库的服务开了吗？