thinkphp 数据库连接报错 SQLSTATE[HY000] [2002] No such file or directory

vim /etc/mysql/mysql.conf.d/mysqld.cnf 

socket          = /var/run/mysqld/mysqld.sock

[Pdo_mysql]
; If mysqlnd is used: Number of cache slots for the internal result set cache
; http://php.net/pdo_mysql.cache_size
pdo_mysql.cache_size = 2000

; Default socket name for local MySQL connects.  If empty, uses the built-in
; MySQL defaults.
; http://php.net/pdo_mysql.default-socket
pdo_mysql.default_socket=/var/run/mysqld/mysqld.sock