MySQL 5.x乱码问题解决

MySQL是一款常用的开源数据库软件，但是对于初次使用者好像并不是太友好，MySQL5.x的版本中默认字符集是latin1也就是我们所知道的ISO-8859-1字符集，这个字符集编码并没有包含汉字，所以我们在使用的时候汉字会出现乱码情况，通过修改数据库默认字符集即可解决。
进入MySQL命令行：

mysql> show variables like '%colla%';
+----------------------+-------------------+
| Variable_name        | Value             |
+----------------------+-------------------+
| collation_connection | gbk_chinese_ci    |
| collation_database   | latin1_swedish_ci |
| collation_server     | latin1_swedish_ci |
+----------------------+-------------------+
3 rows in set, 1 warning (0.00 sec)

mysql> show variables like '%char%';
+--------------------------+---------------------------------------------------------+
| Variable_name            | Value                                                   |
+--------------------------+---------------------------------------------------------+
| character_set_client     | gbk                                                     |
| character_set_connection | gbk                                                     |
| character_set_database   | latin1                                                  |
| character_set_filesystem | binary                                                  |
| character_set_results    | gbk                                                     |
| character_set_server     | latin1                                                  |
| character_set_system     | utf8                                                    |
| character_sets_dir       | C:\Program Files\MySQL\MySQL Server 5.7\share\charsets\ |
+--------------------------+---------------------------------------------------------+
8 rows in set, 1 warning (0.00 sec)

可以看到现在默认的字符集是latin1

找到MySQL的配置文件，windows中的配置文件是my.ini，我的电脑位于C:\ProgramData\MySQL\MySQL Server 5.7，Linux中需要修改的是my.conf文件，具体路径根据你的实际安装位置，分别修改以下节点中的配置：
我使用的5.7中[client]节点的配置需要新增，其余两个节点[mysql]、[mysql]需要打开注释并修改为utf8.

[client]
default-character-set=utf8
[mysql]
default-character-set=utf8
[mysql]
character_set_server=utf8

然后重启MySQL

net stop mysql
net start mysql

再次查看字符集，都已经被修改为utf8字符集

mysql> show variables like '%colla%';
+----------------------+-----------------+
| Variable_name        | Value           |
+----------------------+-----------------+
| collation_connection | gbk_chinese_ci  |
| collation_database   | utf8_general_ci |
| collation_server     | utf8_general_ci |
+----------------------+-----------------+
3 rows in set, 1 warning (0.00 sec)

mysql> show variables like '%char%';
+--------------------------+---------------------------------------------------------+
| Variable_name            | Value                                                   |
+--------------------------+---------------------------------------------------------+
| character_set_client     | gbk                                                     |
| character_set_connection | gbk                                                     |
| character_set_database   | utf8                                                    |
| character_set_filesystem | binary                                                  |
| character_set_results    | gbk                                                     |
| character_set_server     | utf8                                                    |
| character_set_system     | utf8                                                    |
| character_sets_dir       | C:\Program Files\MySQL\MySQL Server 5.7\share\charsets\ |
+--------------------------+---------------------------------------------------------+
8 rows in set, 1 warning (0.00 sec)

为保证编码一致性还可以在创建数据库或者表的时候指定字符集，并在连接串后面指定连接参数：

?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai