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/ |
+--------------------------+----------------------------+
character_set_database和character_set_server的默认字符集还是latin1。
二、最简单的完美修改方法，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
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。注意：[mysqld]字段与[mysql]字段是有区别的。这点在网上没人反馈过。
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/ |
+--------------------------+----------------------------+
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;
网上很多其他方法不能彻底解决这个问题，这个可以完美解决！
附注：MySQL数据库启动，关闭，重启：
开始 sudo /etc/init.d/mysql start
停止 sudo /etc/init.d/mysql stop
重启 sudo /etc/init.d/mysql restart