修改mysql的my.cnf文件中的字符集键值：
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
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
3、在[mysql]字段里加入default-character-set=utf8，如下：
[mysql]
no-auto-rehash
default-character-set=utf8
修改完成后，service mysql restart重启mysql服务就生效。
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/ |
+--------------------------+----------------------------+