java.sql.SQLException: Access denied for user ''@'localhost' (using password: NO)

運行報錯：
    java.sql.SQLException: Access denied for user ''@'localhost' (using password: NO)

解決方案：
    mysql> set password for "root"@"localhost"=old_password('');
           Query OK, 0 rows affected, 1 warning (0.00 sec)