这一次的记录主要是针对mysql5.5版本里面的中文乱码而言，这里用到的操作系统是centos7，数据库是mysql5.5，云平台是阿里云
一、登录MySQL查看用SHOW VARIABLES LIKE ‘character%’;下字符集，显示如下：
+--------------------------+----------------------------+ | Variable_name | Value | +--------------------------+----------------------------+ | character_set_client | utf8 | | character_set_connection | utf8 | | character_set_database | latin1 | | character_set_filesystem | binary | | character_set_results | utf8 | | character_set_server | latin1 | | character_set_system | utf8 | | character_sets_dir | /usr/share/mysql/charsets/ | +--------------------------+----------------------------+ 复制代码
二、修改mysql的my.cnf文件中的字符集键值（注意配置的字段细节）：
1、在[client]字段里加入default-character-set=utf8，如下：
[client] port = 3306 socket = /var/lib/mysql/mysql.sock default-character-set=utf8 复制代码
2、在[mysqld]字段里加入character-set-server=utf8，如下：
[mysqld] port = 3306 socket = /var/lib/mysql/mysql.sock character-set-server=utf8 复制代码
3、在[mysql]字段里加入default-character-set=utf8，如下：
[mysql] no-auto-rehash default-character-set=utf8 复制代码
修改完成后，使用命令：service mysql restart重启mysql服务就生效。注意：[mysqld]字段与[mysql]字段是有区别的。
使用SHOW VARIABLES LIKE ‘character%’;查看，发现数据库编码全已改成utf8。
+--------------------------+----------------------------+ | Variable_name | Value | +--------------------------+----------------------------+ | character_set_client | utf8 | | character_set_connection | utf8 | | character_set_database | utf8 | | character_set_filesystem | binary | | character_set_results | utf8 | | character_set_server | utf8 | | character_set_system | utf8 | | character_sets_dir | /usr/share/mysql/charsets/ | +--------------------------+----------------------------+ 复制代码
‘
4、如果上面的都修改了还乱码，那剩下问题就一定在connection连接层上。解决方法是在发送查询前执行一下下面这句（直接写在SQL文件的最前面）：
SET NAMES ‘utf8’;
它相当于下面的三句指令：
SET character_set_client = utf8;
SET character_set_results = utf8;
SET character_set_connection = utf8;
