连接不到数据库怎么破？

Exception in thread "main" java.sql.SQLException: Access denied for user ''@'localhost' (using password: NO)

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:998)

at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3835)

at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3771)

at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:870)

at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1659)

at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1206)

at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2239)

at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2270)

at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2069)

at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:794)

at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.lang.reflect.Constructor.newInstance(Constructor.java:526)

at com.mysql.jdbc.Util.handleNewInstance(Util.java:389)

at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:399)

at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:325)

at java.sql.DriverManager.getConnection(DriverManager.java:571)

at java.sql.DriverManager.getConnection(DriverManager.java:215)

at com.imooc.db.DBUtil.main(DBUtil.java:22)