MySQL字符集乱码及解决方案分享

吾爱主题阅读：126 2024-04-05 14:03:16 评论：0

前言

字符集是一套符号和编码的规则，不论是在oracle数据库还是在mysql数据库，都存在字符集的选择问题，而且如果在数据库创建阶段没有正确选择字符集，那么可能在后期需要更换字符集，而字符集的更换是代价比较高的操作，也存在一定的风险，所以，我们推荐在应用开始阶段，就按照需求正确的选择合适的字符集，避免后期不必要的调整。

实战

1、安装MySQL数据库

2、乱码演示

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 mysql> show variables like 'character_set%' ; + --------------------------+----------------------------------+ | 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/ local /mysql/share/charsets/ | + --------------------------+----------------------------------+ 8 rows in set (0.00 sec) mysql> insert into test.table10 values (1, '云中鹤' ); Query OK, 1 row affected (0.00 sec) mysql> select * from test.table10; + ------+-----------+ | id | names | + ------+-----------+ | 1 | 云中鹤 | + ------+-----------+ 1 row in set (0.00 sec) mysql> set names latin1; Query OK, 0 rows affected (0.00 sec) mysql> select * from test.table10; + ------+-------+ | id | names | + ------+-------+ | 1 | ??? | + ------+-------+ 1 row in set (0.00 sec) mysql> show variables like 'character_set%' ; + --------------------------+----------------------------------+ | Variable_name | Value | + --------------------------+----------------------------------+ | character_set_client | latin1 #客户端来源数据使用的字符集 | character_set_connection | latin1 # 连接层字符集 | character_set_database | utf8 #当前选中数据库的默认字符集 | character_set_filesystem | binary | character_set_results | latin1 #查询结果字符集 | | character_set_server | utf8 #默认的内部操作字符集 | | character_set_system | utf8 #系统元数据(字段名等)字符集 | character_sets_dir | /usr/ local /mysql/share/charsets/ | + --------------------------+----------------------------------+ 8 rows in set (0.00 sec)

乱码解决办法

从上面可以看出，set names latin1;改变了三个参数.. 只要做到客户端，MySQL character-set-client，table charset三个字符集完全一致就可以保证一定不会有乱码出现。

方式:

1、在mysql命令行模式下执行set names xxx;

1 2	`mysql>` `set` `names utf8;` `Query OK, 0` `rows` `affected (0.01 sec)`

2、登录mysql的时候指定默认字符集

1 2	`[root@node1 ~]# mysql -S /tmp/mysql.sock4` `--defaults-character-set=utf8 #-S 指定多实例mysql的套接字文件，` `使用` `--defaults-character-set 指定默认字符集。`

3、修改/etc/sysconfig/i18n 文件，在my.cnf不指定默认字符集的情况下。

1 2	`vim /etc/sysconfig/i18n` `LANG=` `'zh_CN.UTF-8'` `#如果my.cnf不指定，默认使用系统字符集`

4、修改my.cnf 文件，下面两个字段在任意一个字段都是可以的。

1 2	`[client]` `default` `-` `character` `-` `set` `=latin1`

1 2	`[mysql]` `default` `-` `character` `-` `set` `=latin1`

前两种1,2是临时解决方案，后面两种3,4是永久有效的方案

查看字符集

1、查看系统当前字符集设置，修改之后登陆mysql执行。show variables lile 'character_set%';

1 2 3 4 5 6 7 8 9 10 11 12 mysql> show variables like 'character_set%' ;#我修改的为utf8，所以客户端的三个参数都是utf8.你可以自行设置字符集。 + --------------------------+----------------------------------+ | 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/ local /mysql/share/charsets/ |

2、mysql常用字符集。执行命令show character set; 查看系统支持字符集。

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 mysql> show character set ; + ----------+-----------------------------+---------------------+--------+ | Charset | Description | Default collation | Maxlen | + ----------+-----------------------------+---------------------+--------+ | big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 | | dec8 | DEC West European | dec8_swedish_ci | 1 | | cp850 | DOS West European | cp850_general_ci | 1 | | hp8 | HP West European | hp8_english_ci | 1 | | koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 | | latin1 | cp1252 West European | latin1_swedish_ci | 1 | #常用 | latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 | | swe7 | 7bit Swedish | swe7_swedish_ci | 1 | | ascii | US ASCII | ascii_general_ci | 1 | | ujis | EUC-JP Japanese | ujis_japanese_ci | 3 | | sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 | | hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 | | tis620 | TIS620 Thai | tis620_thai_ci | 1 | | euckr | EUC-KR Korean | euckr_korean_ci | 2 | | koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 | | gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 | | greek | ISO 8859-7 Greek | greek_general_ci | 1 | | cp1250 | Windows Central European | cp1250_general_ci | 1 | | gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 | #常用 | latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 | | armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 | | utf8 | UTF-8 Unicode | utf8_general_ci | 3 |#常用 | ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 | | cp866 | DOS Russian | cp866_general_ci | 1 | | keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 | | macce | Mac Central European | macce_general_ci | 1 | | macroman | Mac West European | macroman_general_ci | 1 | | cp852 | DOS Central European | cp852_general_ci | 1 | | latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 | | utf8mb4 | UTF-8 Unicode | utf8mb4_general_ci | 4 | #常用 | cp1251 | Windows Cyrillic | cp1251_general_ci | 1 | | utf16 | UTF-16 Unicode | utf16_general_ci | 4 | | cp1256 | Windows Arabic | cp1256_general_ci | 1 | | cp1257 | Windows Baltic | cp1257_general_ci | 1 | | utf32 | UTF-32 Unicode | utf32_general_ci | 4 | | binary | Binary pseudo charset | binary | 1 | | geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 | | cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 | | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 | + ----------+-----------------------------+---------------------+--------+ 39 rows in set (0.00 sec)

字符集选择

1、如果处理各种各样的文字，发布到不同语言国家地区，选择Unicode。，对mysql对号utf-8。

2、只需中文，数据量很大，性能要求也高，选择gbk.。

3、处理移动物联网业务，选utf8mb4

建议在能够完全满足应用的前提下，尽量使用小的字符集。因为更小的字符集意味着能够节省空间、减少网络传输字节数，同时由于存储空间的较小间接的提高了系统的性能。

服务器字符集设置

1 2 3 [mysqld] ... character - set -server=utf8 #添加这条语句，可设置服务器端字符集。

mysql服务端重新启动后，这两个参数会改变为设定值。

1 2	`\| character_set_server \| utf8` `\| character_set_database \| utf8`

切换字符集

将一种编码的数据库转换为另一种编码的数据。

1	`alter` `database` `dbname` `character` `set` `xxx; #只能对以后的数据有效，对之前的数据无效。基本不使用`

常用转换数据库字符集方案

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 mysqldump -S /tmp/mysql.sock4 --default-character-set=utf8 -d test > /data/test-`date +%F`.sql #1、导出表结构而不导出数据 vim /data/test-` date +%F`.sql DROP TABLE IF EXISTS `table10`; /*!40101 SET @saved_cs_client = @@character_set_client */; /*!40101 SET character_set_client = utf8 */; CREATE TABLE `table10` ( `id` int (11) DEFAULT NULL , `names` char (20) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=utf8; #2、这里的CHARSET改为你想要修改的字符集 mysqldump -S /tmp/mysql.sock4 --extended-insert --no-create-info test > /data/test-data-`date +%F`.sql #3、导出数据内容 vim /data/test-data-` date +%F`.sql LOCK TABLES `table10` WRITE; set names utf8; #4、这一行是多加的，自己指定想要转换的字符集 INSERT INTO `table10` VALUES (1, '云中鹤' ); UNLOCK TABLES; mysql> create database if not exists test; #5、创建数据库，存储转换后的数据 Query OK, 1 row affected, 0 warning (0.00 sec) mysql -S /tmp/mysql.sock4 test < /data/test-` date +%F`.sql #6、导入表结构 mysql -S /tmp/mysql.sock4 test < /data/test-data-2015-09-25.sql #7、导入表数据