Question

message = new String(("round " + id).getBytes("UTF-8"));

conn = DriverManager.getConnection("jdbc:mysql://" + host + "/" + db + "?useUnicode=true&characterEncoding=UTF-8&"
              + "user=" + login + "&password=" + password);

当我在数据库中插入哪个编码为UTF-8 CI时，得到类似�� 179的内容，java文件编码是utf-8，我做错了什么？

+--------------------------+----------------------------+
| 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/ |
+--------------------------+----------------------------+

Answer 1

通常，MySQL附带一个预定义系统变量列表。如果要列出它们，可以打开MySQL提示符并键入：

mysql> SHOW VARIABLES LIKE  'char%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | latin1                     |
| character_set_connection | latin1                     |
| character_set_database   | latin1                     |
| character_set_filesystem | binary                     |
| character_set_results    | latin1                     |
| character_set_server     | latin1                     |
| character_set_system     | latin1                     |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+

如图所示，MySQL的默认编码为latin1。要更改它，您需要编辑 my.cnf 文件并添加以下行：

[client]
default-character-set=utf8

[mysql]
default-character-set=utf8


[mysqld]
collation-server = utf8_unicode_ci
init-connect='SET NAMES utf8'
character-set-server = utf8

配置 my.cnf 文件并重新启动MySQL服务器时，您会注意到差异。

修改：您可以像这样设置JDBC DriverManager的编码：

DriverManager.getConnection("jdbc:mysql://" + host + "/" + db + "?useUnicode=true&" + "user=" + login + "&password=" + password + "&characterEncoding=utf8");

Answer 2

除了在java jdbc中设置连接字符串外，还有另一种更改mysql字符集的方法：

1）在创建数据库和表时指定utf8

    //database
    CREATE DATABASE IF NOT EXISTS databasename 
    default charset utf8
    COLLATE utf8_general_ci;

    //table
    CREATE TABLE  `Extenics`.`BE_headset` (
  `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(255) NOT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=30 DEFAULT CHARSET=utf8;

2）或在创建后改变它（我不鼓励这样做）

ALTER DATABASE db_name

    [[DEFAULT] CHARACTER SET charset_name]

    [[DEFAULT] COLLATE collation_name]

请参阅mysql以获取更多帮助。

为什么java字符串在MYSQL中没有保存为UTF-8？

2 个答案: