MySQL编码修改--> 支持emoji表情

记线上服务的一次维护

线上服务一直跑的好好地，忽然今天客户说分享作品提示失败，自己去试了一下也能分享成功，只能去后台查早上七点多的日志记录。结果发现 果然后台报的有错

org.springframework.jdbc.UncategorizedSQLException:
### Error updating database.  Cause: java.sql.SQLException: Incorrect string value: '\xF0\x9F\x98\x84' for column 'title' at row 1
### The error may involve com.deepai.paipai.dao.PaipaiUserPictureMapper.insertSelective-Inline
### The error occurred while setting parameters
### SQL: insert into paipai_user_picture ( userId, createTime, url, surl, title, standby1, standby2, standby4, visibleType, hasReprinted )  values ( ?, ?, ?, ?, ?, ?, ?, ?, ?, ? )
### Cause: java.sql.SQLException: Incorrect string value: '\xF0\x9F\x98\x84' for column 'title' at row 1
; uncategorized SQLException for SQL []; SQL state [HY000]; error code [1366]; Incorrect string value: '\xF0\x9F\x98\x84' for column 'title' at row 1; nested exception is java.sql.SQLException: Incorrect string value: '\xF0\x9F\x98\x84' for column 'title' at row 1
at
......省略n行
Caused by: java.sql.SQLException: Incorrect string value: '\xF0\x9F\x98\x84' for column 'title' at row 1
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
......省略n行 org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:358)
... 57 more

经过查资料也了解到 这是因为存储的信息包含了emoji表情（是4个字节的字符）而MySQL的utf8编码只支持3字节的数据。既然问题确定了，那就找对应的解决方案就好了。使用MySQL的 utf8mb4 编码即可。

'确认   mysql -V >= 5.5.3   &&  MySQL驱动 >= 5.1.13   (这个是查资料看到的，有兴趣的朋友可以验证一下)'

'vim /etc/my.cnf (一般在这个位置) 直接在末尾添加以下配置'

[client]
default-character-set = utf8mb4
[mysql]
default-character-set = utf8mb4
[mysqld]
character-set-client-handshake = FALSE
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci
init_connect='SET NAMES utf8mb4'

SHOW VARIABLES WHERE Variable_name LIKE 'character_set_%' OR Variable_name LIKE 'collation%';

'效果如下即可'

ALTER DATABASE paipai360 CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;

ALTER TABLE paipai_user_picture CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;

'进行如下修改 去掉 characterEncoding=utf8 让它自己去匹配或者改为 utf8mb4 '
'添加 autoReconnect=true '

jdbc.writeJdbcUrl = jdbc:mysql://xx.xx.xxx.xx:3306/paipai360?useUnicode=true&autoReconnect=true