mysql存储表情字符

表情字符串是4个字节
（1）升级mysql到5.5以上才行
（2）config/database.yml设置
     #encoding: utf8mb4
     #charset: utf8mb4
     #collation: utf8mb4_unicode_ci
     encoding: utf8mb4这句话添加到各个环境下
（3）本地报
Character set 'utf8mb4' is not a compiled character set and is not specified in the '/usr/share/mysql/charsets/Index.xml' file
Mysql2::Error: Can't initialize character set utf8mb4 (path: /usr/share/mysql/charsets/)
（4）修改本地（137）mysql上配置
        vi /etc/my.cnf
       port            = 3306
      socket          = /home/mysql/mysql/mysql.sock
      character_set_server=utf8mb4 在上面两句下添加这句
（5）重启mysql   
      service mysqld start    有些可能是mysql
（6）修改 /usr/share/mysql/charsets/Index.xml 文件
     把开头name的utf8改成utf8mb4 其它不用修改，完成