XML 架构。Base64binary 类型 vs String 类型
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XML Schema. Base64binary type vs String type
提问by kirill.login
I need to decode a Base64 string from some XML element. Is there any difference between an element defined by type="xs:base64binary"and an element defined by type="xs:string"? Some XSD developers refuse to mark encoded strings as a base64binary. If there is no difference, what is the use of type="xs:base64binary"?
我需要从某个 XML 元素解码 Base64 字符串。由type="xs:base64binary"定义的元素和由定义的元素之间有什么区别type="xs:string"吗？一些 XSD 开发人员拒绝将编码字符串标记为 base64binary。如果没有区别，有什么用type="xs:base64binary"？
采纳答案by CodeManX
If I understand the specscorrectly, there is a semantic difference.
如果我正确理解规范，则存在语义差异。
A base64Binaryelement contains arbitrary, binary data that has been encoded as base64, which makes it basically a string (or at least string-compatible).
甲base64Binary元素包含已被编码为base64任意的，二进制数据，这使得它基本上是一个字符串（或至少串兼容）。
On the other hand, strings contain printable characters, which (usually) make up words and sentences (natural language). They cannot contain arbitrary (binary) data, because certain characters aren't allowed.
另一方面，字符串包含可打印的字符，这些字符（通常）构成单词和句子（自然语言）。它们不能包含任意（二进制）数据，因为某些字符是不允许的。
You can use base64Binaryto indicate that the decoded data is not suitable for human consumption, where as stringis readable/printable.
您可以使用base64Binary来指示解码的数据不适合人类消费，而string可读/可打印。
回答by kjhughes
There definitely is a difference between base64Binaryand stringin XSD:
XSDbase64Binary和stringXSD之间肯定存在差异：
- base64Binaryrepresents binary data encoded in Base64. Its value spaceis the set of fixed length binary octets. Its
lexical space is limited to
a-z,A-Z,0-9,+,/,=, plus whitespace. - stringrepresents character data. Its value spaceis the set of finite-length sequences of characters. Its lexical space is unconstrained beyond having to consist of XML characters.
