Java char 以什么编码存储? [英] In what encoding is a Java char stored in?

问题描述

Java char 类型是否保证以任何特定编码存储?

Is the Java char type guaranteed to be stored in any particular encoding?

我错误地表述了这个问题.我想问的是char文字是否保证使用任何特定的编码?

I phrased this question incorrectly. What I meant to ask is are char literals guaranteed to use any particular encoding?

推荐答案

存储"在哪里?Java 中的所有字符串都以 UTF-16 表示.当写入文件、通过网络发送或其他任何方式时，它会使用您指定的任何字符编码发送.

"Stored" where? All Strings in Java are represented in UTF-16. When written to a file, sent across a network, or whatever else, it's sent using whatever character encoding you specify.

专门针对 char 类型，请参阅 字符文档.具体来说:char 数据类型......基于原始 Unicode 规范，该规范将字符定义为固定宽度的 16 位实体."因此，将 char 转换为 int 将始终为您提供 UTF-16 值 if char 实际上包含一个字符从那个字符集.如果您只是在 char 中插入一些随机值，它显然不一定是有效的 UTF-16 字符，同样，如果您使用错误的编码读取字符.文档继续讨论补充 UTF-16 字符如何只能由 int 表示，因为 char 没有足够的空间来容纳它们，如果你'在这个级别上运行，熟悉这些语义可能很重要.

Specifically for the char type, see the Character docs. Specifically: "The char data type ... are based on the original Unicode specification, which defined characters as fixed-width 16-bit entities." Therefore, casting char to int will always give you a UTF-16 value if the char actually contains a character from that charset. If you just poked some random value into the char, it obviously won't necessarily be a valid UTF-16 character, and likewise if you read the character in using a bad encoding. The docs go on to discuss how the supplementary UTF-16 characters can only be represented by an int, since char doesn't have enough space to hold them, and if you're operating at this level, it might be important to get familiar with those semantics.

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