代码如下：
<code><?php$mysqli = new mysqli('localhost', 'root', '184995511', 'cg_levi');if ($mysqli->connect_error) { die('Connect Error (' . $mysq<em style="color:transparent">本@文来源[email protected]搞@^&代*@码网(</em><q>搞代gaodaima码</q>li->connect_errno . ') ' . $mysqli->connect_error);};echo 'ok';</code>
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如果上面连接地址为’localhost’就会报错，如下：
Warning: mysqli::mysqli(): (HY000/2002): No such file or directory in /mnt/www/cglevi/publichtml/mysql.php on line 2Connect Error (2002) No such file or directory
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将’localhost’修改为’127.0.0.1’之后链接正常
查看了hosts没有问题，如下：
<code>127.0.0.1 localhost::1 localhost localhost.localdomain localhost6 localhost6.localdomain6/etc/hosts (END) </code>
查看mysql状态，没有问题，如下：
<code>mysql> status;--------------mysql Ver 14.14 Distrib 5.6.10, for Linux (x86_64) using EditLine wrapperConnection id: 860Current database: Current user: root@localhostSSL: Not in useCurrent pager: stdoutUsing outfile: ''Using delimiter: ;Server version: 5.6.10 MySQL Community Server (GPL)Protocol version: 10Connection: Localhost via UNIX socketServer characterset: latin1Db characterset: latin1Client characterset: utf8Conn. characterset: utf8UNIX socket: /var/lib/mysql/mysql.sockUptime: 13 hours 13 min 50 secThreads: 1 Questions: 11900 Slow queries: 0 Opens: 100 Flush tables: 1 Open tables: 80 Queries per second avg: 0.249--------------</code>
请问如何解决？
回复内容：
代码如下：
<code><?php$mysqli = new mysqli('localhost', 'root', '184995511', 'cg_levi');if ($mysqli->connect_error) { die('Connect Error (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error);};echo 'ok';</code>
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如果上面连接地址为’localhost’就会报错，如下：
Warning: mysqli::mysqli(): (HY000/2002): No such file or directory in /mnt/www/cglevi/publichtml/mysql.php on line 2Connect Error (2002) No such file or directory
-
将’localhost’修改为’127.0.0.1’之后链接正常
查看了hosts没有问题，如下：
<code>127.0.0.1 localhost::1 localhost localhost.localdomain localhost6 localhost6.localdomain6/etc/hosts (END) </code>
查看mysql状态，没有问题，如下：
<code>mysql> status;--------------mysql Ver 14.14 Distrib 5.6.10, for Linux (x86_64) using EditLine wrapperConnection id: 860Current database: Current user: root@localhostSSL: Not in useCurrent pager: stdoutUsing outfile: ''Using delimiter: ;Server version: 5.6.10 MySQL Community Server (GPL)Protocol version: 10Connection: Localhost via UNIX socketServer characterset: latin1Db characterset: latin1Client characterset: utf8Conn. characterset: utf8UNIX socket: /var/lib/mysql/mysql.sockUptime: 13 hours 13 min 50 secThreads: 1 Questions: 11900 Slow queries: 0 Opens: 100 Flush tables: 1 Open tables: 80 Queries per second avg: 0.249--------------</code>
请问如何解决？
开始的回答有点不严谨，估计也没有解决问题，修改了答案：
问题出现的原因：
当主机填写为localhost时MySQL会采用 unix domain socket连接，当主机填写为127.0.0.1时MySQL会采用TCP/IP的方式连接。使用Unix socket的连接比TCP/IP的连接更加快速与安全。这是MySQL连接的特性，可以参考官方文档的说明4.2.2. Connecting to the MySQL Server：
<code>On Unix, MySQL programs treat the host name localhost specially, in a way that is likely different from what you expect compared to other network-based programs. For connections to localhost, MySQL programs attempt to connect to the local server by using a Unix socket file. This occurs even if a --port or -P option is given to specify a port number. To ensure that the client makes a TCP/IP connection to the local server, use --host or -h to specify a host name value of 127.0.0.1, or the IP address or name of the local server. You can also specify the connection protocol explicitly, even for localhost, by using the --protocol=TCP option.</code>
这个问题有以下几种解决方法：
- 使用TCP/IP代替Unix socket。即在连接的时候将localhost换成127.0.0.1。
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修改MySQL的配置文件my.cnf，指定mysql.socket的位置：
/var/lib/mysql/mysql.sock (你的mysql.socket路径)。
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直接在php建立连接的时候指定my.socket的位置（官方文档：mysqli_connect）。比如：
$db = new MySQLi(‘localhost’, ‘root’, ‘root’, ‘my_db’, ‘3306’, ‘/var/run/mysqld/mysqld.sock’)
如果哪里没有说清楚或者说错了，欢迎提出了～～
参考这个问题： http://segmentfault.com/q/1010000000320989
提问之前记得先搜索。
转载请注明原文链接：mysqli不能使用localhost，请问这是怎么回事？
