MySQL emoji支持

概述

utf-8編碼可能2個字節、3個字節、4個字節的字符，可是MySQL的utf8編碼只支持3字節的數據，而移動端的表情數據是4個字節的字符。若是直接往採用utf-8編碼的數據庫中插入表情數據，Java程序中將報SQL異常：

java.sql.SQLException: Incorrect string value: ‘\xF0\x9F\x92\x94’ for column ‘name’ at row 1

針對該問題處理最簡單的方式是更改數據庫的編碼爲utf8mb4，直接將問題扼殺在搖籃中。

前置條件

• MySQL服務器版本不能低於5.5.3;
• MySQL驅動版本不能低於5.1.13;

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_general_ci 
init_connect='SET NAMES utf8mb4'

重啓數據庫。

檢查數據庫變量

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	utf8mb4
collation_connection	utf8mb4_general_ci
collation_database	utf8mb4_general_ci
collation_server	utf8mb4_general_ci

更改現有數據庫、表、字段編碼

ALTER DATABASE `ticketdb` CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;
ALTER TABLE `ticket_description` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;
ALTER TABLE `ticket_description`
MODIFY COLUMN `description`  text CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL COMMENT '工單描述' AFTER `id`;

如此一來，emoji表情應該不是問題了。