用于 MySQL 配置的 JDBC url 使用 utf8 字符编码

2021-12-21 00:00:00 utf-8 encoding mysql jdbc collation

我已经手动配置了/etc/mysql/my.cnf 以使用utf8.见下文:

I have configured /etc/mysql/my.cnf manually to use utf8. See below:

[mysqld]
character-set-server=utf8
character-sets-dir=/usr/share/mysql/charsets

[mysql]
character-sets-dir=/usr/share/mysql/charsets default-character-set=utf8

[mysqladmin]
character-sets-dir=/usr/share/mysql/charsets default-character-set=utf8

[mysqlcheck]
character-sets-dir=/usr/share/mysql/charsets default-character-set=utf8

[mysqldump]
character-sets-dir=/usr/share/mysql/charsets default-character-set=utf8

[mysqlimport]
character-sets-dir=/usr/share/mysql/charsets default-character-set=utf8

[mysqlshow]
character-sets-dir=/usr/share/mysql/charsets default-character-set=utf8

[client]
character-sets-dir=/usr/share/mysql/charsets default-character-set=utf8

来自控制台:

mysql> show variables like 'char%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.01 sec)

应用配置

现在对于 web 应用程序，我在 Tomcat 的 context.xml

url="jdbc:mysql://localhost:3306/test?autoReconnect=true&useUnicode=true&characterEncoding=UTF-8"

url="jdbc:mysql://localhost:3306/test?autoReconnect=true&useUnicode=true&characterEncoding=UTF-8&characterSetResults=utf8&connectionCollation=utf8_general_ci"

以上不起作用，并为我提供以下应用程序.

Above does not work and gives me following for the application.

show variables like 'char%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8mb4                    |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8mb4                    |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+

<小时>

这里可能有什么问题?为什么它显示 utf8mb4 而不是 utf8?

推荐答案

您可能需要处理以下问题:

You may have to do with the following:

MySQL Connector/J 的变化5.1.13 (2010-06-24)

  • Connector/J 不支持 utf8mb4 用于服务器 5.5.2 和更新版本.

  • Connector/J did not support utf8mb4 for servers 5.5.2 and newer.

Connector/J 现在自动检测使用 character_set_server=utf8mb4 配置的服务器或将使用 characterEncoding=... 传递的 Java 编码 utf-8 视为 utf8mb4 中的 SET NAMES= 调用它在建立连接时进行.(错误 #54175)

Connector/J now auto-detects servers configured with character_set_server=utf8mb4 or treats the Java encoding utf-8 passed using characterEncoding=... as utf8mb4 in the SET NAMES= calls it makes when establishing the connection. (Bug #54175)

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