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做数据迁移后，通过ui发现有日文数据是乱码，通过ui直接修改日文则显示正常.
查了下资料，mysql字符集的作用如下：
MySQL字符集设置
• 系统变量：
– character_set_server：默认的内部操作字符集
– character_set_client：客户端来源数据使用的字符集
– character_set_connection：连接层字符集
– character_set_results：查询结果字符集
– character_set_database：当前选中数据库的默认字符集
– character_set_system：系统元数据(字段名等)字符集
– 还有以collation_开头的同上面对应的变量，用来描述字符序。
于是：
mysql> SHOW VARIABLES LIKE ‘collation_%‘;
+----------------------+-----------------+
| Variable_name | Value |
+----------------------+-----------------+
| collation_connection | utf8_general_ci |
| collation_database | utf8_general_ci |
| collation_server | latin1_swedish_ci|
+----------------------+-----------------+
3 rows in set (0.00 sec)
而通过jdbc 的配置制定了连接字符集，所以通过ui设定日文无问题：
jdbc\:mysql\://10.1.0.198\:3306/mytestui?zeroDateTimeBehavior\=convertToNull&useUnicode\=true&characterEncoding\=utf-8
而导入数据时，由于没有明确指定连接字符集，mysql会使用默认的字符集进行导入操作,而默认字符集是 latin1_swedish_ci：
mysql -h127.0.0.1 -umyaccount -p <./patch.sql
解决方案1：
修改系统的默认字符集为utf-8
解决方案2：
导入sql文件时，指定字符集：
mysql -h127.0.0. -umyaccount -p <.patch.sql --default-character-set=utf8
Mysql explain:
Use charset_name as the default character set for the client and connection.
A common issue that can occur when the operating system uses utf8 or another
multi-byte character
set is that output from the mysql client is formatted incorrectly, due to
the fact that the MySQL client uses the latin1 character set by default. You
can usually fix such issues by using this option to force the client to use the
system character set instead
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原文地址：http://www.cnblogs.com/dogharry/p/4614242.html
