今天在本地搭建环境之后，app端写入后台发现中文无法正确写入，全部显示为???，摸索了一会，设置过tomcat环境也设置过数据库字符集，结果还是不行，后来咨询大佬们，尝试如下：
先在数据库中查询字符编码：
show VARIABLES like 'char%';
结果如下：
+--------------------------+----------------------------------------+
| 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 | latin1 |
| character_set_system | utf8 |
| character_sets_dir | J:\mysql-5.7.16-winx64\share\charsets\ |
+--------------------------+----------------------------------------+
发现character_set_server这是个叛徒！原因是MySQL的默认编码是拉丁，所以打开mysql的安装目录，找到my.ini，在[mysqld]最后下面加上
character_set_server=utf8
init_connect='SET NAMES utf8'
之后重启MySQL。
再查看一下编码，结果变为：
+--------------------------+----------------------------------------+
| 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 | J:\mysql-5.7.16-winx64\share\charsets\ |
敌军被干掉了，测试也一切正常了~
