使mysql支持emoji

在微信開發過程當中，有些用戶的暱稱是特殊表情，致使服務器端存儲時發生錯誤：

Caused by: java.sql.SQLException: Incorrect string value: '\xF0\x9F\x98\x84' for column 'review' at row 1
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1074)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4096)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4028)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2490)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2651)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2734)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2458)

解決方案：將Mysql的編碼從utf8轉換成utf8mb4。

1.修改my.cnf:

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

2.在Connector/J的鏈接參數中，不要加characterEncoding參數。 不加這個參數時，默認值就時autodetect。

3.將已經建好的表也轉換成utf8mb4

ALTER TABLE `TABLE_NAME` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci; （將TABLE_NAME替換成你的表名）

4.將須要使用emoji的字段設置類型爲utf8mb4

ALTER TABLE `TABLE_NAME`MODIFY COLUMN `COLUMN_NAME`  text CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;