Verwenden Sie immer UTF-8

Question

Ich richte einen neuen Server ein und möchte vollständige UTF-8-Unterstützung in meiner Webanwendung. Ich habe dies in der Vergangenheit bereits auf vorhandenen Servern versucht, schien aber immer auf ISO-8859-1 zurückgreifen zu müssen. Wo genau muss ich die Kodierung/den Zeichensatz einstellen? Ich weiß, dass ich dazu Apache, MySQL und PHP konfigurieren muss. Gibt es eine Standard-Checkliste, der ich folgen kann, oder kann ich vielleicht eine Fehlerbehebung durchführen, wo die Nichtübereinstimmung auftritt? Dies funktioniert für neue Linux-Dienste, auf denen MySQL5, PHP, 5 und Apache2 ausgeführt werden

P粉854119263 · Answer

我想在 chazomaticus 的出色答案中添加一件事一个>：

也不要忘记 META 标记（像这样，或者它的 HTML4 或 XHTML 版本):

这看起来微不足道，但 IE7 之前曾给我带来过问题。

我做的一切都是正确的；数据库、数据库连接和Content-Type HTTP标头都设置为UTF-8，在所有其他浏览器中都运行良好，但Internet Explorer仍然坚持使用“西欧”编码。

原来该页面缺少 META 标记。添加即可解决问题。

编辑：

W3C 实际上有一个相当大的专门讨论 I18N 的部分。他们有许多与此问题相关的文章 - 描述了 HTTP、(X)HTML 和 CSS 方面的内容：

他们建议同时使用 HTTP 标头和 HTML 元标记（或者在 XHTML 充当 XML 的情况下使用 XML 声明）。

P粉763662390 · Answer

数据存储：

Specify the utf8mb4 character set on all tables and text columns in your database. This makes MySQL physically store and retrieve values encoded natively in UTF-8. Note that MySQL will implicitly use utf8mb4 encoding if a utf8mb4_* collation is specified (without any explicit character set).
In older versions of MySQL (< 5.5.3), you'll unfortunately be forced to use simply utf8, which only supports a subset of Unicode characters. I wish I were kidding.

数据访问：

In your application code (e.g. PHP), in whatever DB access method you use, you'll need to set the connection charset to utf8mb4. This way, MySQL does no conversion from its native UTF-8 when it hands data off to your application and vice versa.
某些驱动程序提供自己的机制来配置连接字符集，该机制既更新其自身的内部状态，又通知 MySQL 连接上要使用的编码 - 这通常是首选方法。在 PHP 中：
- If you're using the PDO abstraction layer with PHP ≥ 5.3.6, you can specify charset in the DSN:
```
$dbh = new PDO('mysql:charset=utf8mb4');
```
- If you're using mysqli, you can call set_charset():
```
$mysqli->set_charset('utf8mb4');       // object oriented style
  mysqli_set_charset($link, 'utf8mb4');  // procedural style
```
- If you're stuck with plain mysql but happen to be running PHP ≥ 5.2.3, you can call mysql_set_charset.
If the driver does not provide its own mechanism for setting the connection character set, you may have to issue a query to tell MySQL how your application expects data on the connection to be encoded: SET NAMES 'utf8mb4'.
The same consideration regarding utf8mb4/utf8 applies as above.

输出：

UTF-8 should be set in the HTTP header, such as Content-Type: text/html; charset=utf-8. You can achieve that either by setting default_charset in php.ini (preferred), or manually using header() function.
如果您的应用程序将文本传输到其他系统，它们还需要了解字符编码。对于 Web 应用程序，必须告知浏览器发送数据的编码（通过 HTTP 响应标头或 HTML 元数据）。
When encoding the output using json_encode(), add JSON_UNESCAPED_UNICODE as a second parameter.

输入：

浏览器将以为文档指定的字符集提交数据，因此无需对输入执行任何特殊操作。
In case you have doubts about request encoding (in case it could be tampered with), you may verify every received string as being valid UTF-8 before you try to store it or use it anywhere. PHP's mb_check_encoding() does the trick, but you have to use it religiously. There's really no way around this, as malicious clients can submit data in whatever encoding they want, and I haven't found a trick to get PHP to do this for you reliably.

其他代码注意事项：

显然，您将提供的所有文件（PHP、HTML、JavaScript 等）都应使用有效的 UTF-8 进行编码。
You need to make sure that every time you process a UTF-8 string, you do so safely. This is, unfortunately, the hard part. You'll probably want to make extensive use of PHP's mbstring extension.
PHP's built-in string operations are not by default UTF-8 safe. There are some things you can safely do with normal PHP string operations (like concatenation), but for most things you should use the equivalent mbstring function.
要知道您在做什么（阅读：不要搞砸），您确实需要了解 UTF-8 以及它如何在尽可能最低的级别上工作。查看 utf8.com 中的任何链接，获取一些很好的资源，以了解您需要了解的所有内容。 p>