SQLSTATE[HY000] [2002] Connection refused

FILE: /alidata/www/yanglao/ThinkPHP/Library/Think/Db/Driver.class.php 　LINE: 116

#0 /alidata/www/yanglao/ThinkPHP/Library/Think/Db/Driver.class.php(116): E('SQLSTATE[HY000]...')
#1 /alidata/www/yanglao/ThinkPHP/Library/Think/Db/Driver.class.php(1096): Think\Db\Driver->connect()
#2 /alidata/www/yanglao/ThinkPHP/Library/Think/Db/Driver/Mysql.class.php(47): Think\Db\Driver->initConnect(true)
#3 /alidata/www/yanglao/ThinkPHP/Library/Think/Model.class.php(134): Think\Db\Driver\Mysql->getFields('ueo16_user')
#4 /alidata/www/yanglao/ThinkPHP/Library/Think/Model.class.php(122): Think\Model->flush()
#5 /alidata/www/yanglao/ThinkPHP/Library/Think/Model.class.php(1437): Think\Model->_checkTableInfo()
#6 /alidata/www/yanglao/ThinkPHP/Library/Think/Model.class.php(97): Think\Model->db(0, '', true)
#7 /alidata/www/yanglao/ThinkPHP/Common/functions.php(621): Think\Model->__construct('User', '', '')
#8 /alidata/www/yanglao/Home/Common/Controller/PublicController.class.php(33): M('User')
#9 /alidata/www/yanglao/ThinkPHP/Common/functions.php(681): Common\Controller\PublicController->__construct()
#10 /alidata/www/yanglao/ThinkPHP/Library/Think/App.class.php(89): controller('Index', '')
#11 /alidata/www/yanglao/ThinkPHP/Library/Think/App.class.php(202): Think\App::exec()
#12 /alidata/www/yanglao/ThinkPHP/Library/Think/Think.class.php(120): Think\App::run()
#13 /alidata/www/yanglao/ThinkPHP/ThinkPHP.php(103): Think\Think::start()
#14 /alidata/www/yanglao/index.php(10): require('/alidata/www/ya...')
#15 {main}