mysql emoji支持

转自http://blog.csdn.net/kinginblue/article/details/52445143

1.改 Mysql 配置文件 my.cnf(默认位置/etc/my.cnf)
    [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'

2.改已有的 database、table 和 column 字符集
    msql> ALTER DATABASE database_name CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;
    msql> ALTER TABLE table_name CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
    msql> ALTER TABLE table_name CHANGE column column_name VARCHAR(191) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

    其中的 database_name、table_name、column_name 要替换成你对应的数据库名、表名、列名。VARCHAR 的长度值也是。

3.重启 Mysql 并检查更改后的字符集设置
    service mysql restart
    查看字符集设置：
    msql> SHOW VARIABLES WHERE Variable_name LIKE 'character_set_%' OR Variable_name LIKE 'collation%';
    +--------------------------+--------------------+
    | Variable_name            | Value              |
    +--------------------------+--------------------+
    | character_set_client    | utf8mb4            |
    | character_set_connection | utf8mb4            |
    | character_set_database  | utf8mb4            |
    | character_set_filesystem | binary            |
    | character_set_results    | utf8mb4            |
    | character_set_server    | utf8mb4            |
    | character_set_system    | utf8              |
    | collation_connection    | utf8mb4_unicode_ci |
    | collation_database      | utf8mb4_unicode_ci |
    | collation_server        | utf8mb4_unicode_ci |
    +--------------------------+--------------------+
    rows in set (0.00 sec)

4.使用 Druid 数据源配置，添加了一个配置：
    <property name="connectionInitSqls" value="set names utf8mb4;"/>

5.jdbc.url=jdbc:mysql://localhost:3306/demo?autoReconnect=true&failOverReadOnly=false
    去掉characterEncoding=utf8