JSON格式本身不支持二进制数据。二进制数据必须转义，以便可以将其放在JSON中的字符串元素中(即使用反斜杠转义的双引号中的零或多个Unicode字符)。
转义二进制数据的一个明显方法是使用Base64。然而，Base64有很高的处理开销。此外，它将3个字节扩展为4个字符，导致数据大小增加约33%。
其中一个用例是CDMI云存储API规范的0.8版草案。您可以使用JSON通过REST-Webservice创建数据对象，例如:
PUT /MyContainer/BinaryObject HTTP/1.1
Host: cloud.example.com
Accept: application/vnd.org.snia.cdmi.dataobject+json
Content-Type: application/vnd.org.snia.cdmi.dataobject+json
X-CDMI-Specification-Version: 1.0
{
"mimetype" : "application/octet-stream",
"metadata" : [ ],
"value" : "TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbmx5IGJ5IGhpcyByZWFzb24sIGJ1dCBieSB0aGlz
IHNpbmd1bGFyIHBhc3Npb24gZnJvbSBvdGhlciBhbmltYWxzLCB3aGljaCBpcyBhIGx1c3Qgb2Yg
dGhlIG1pbmQsIHRoYXQgYnkgYSBwZXJzZXZlcmFuY2Ugb2YgZGVsaWdodCBpbiB0aGUgY29udGlu
dWVkIGFuZCBpbmRlZmF0aWdhYmxlIGdlbmVyYXRpb24gb2Yga25vd2xlZGdlLCBleGNlZWRzIHRo
ZSBzaG9ydCB2ZWhlbWVuY2Ugb2YgYW55IGNhcm5hbCBwbGVhc3VyZS4=",
}
是否有更好的方法和标准方法将二进制数据编码为JSON字符串?
While it is true that base64 has ~33% expansion rate, it is not necessarily true that processing overhead is significantly more than this: it really depends on JSON library/toolkit you are using. Encoding and decoding are simple straight-forward operations, and they can even be optimized wrt character encoding (as JSON only supports UTF-8/16/32) -- base64 characters are always single-byte for JSON String entries.
For example on Java platform there are libraries that can do the job rather efficiently, so that overhead is mostly due to expanded size.
我同意之前的两个答案:
base64是简单的，常用的标准，所以不太可能找到更好的标准来与JSON一起使用(base-85用于postscript等;但仔细想想，这些好处充其量只是边际的)
编码前压缩(解码后压缩)可能很有意义，这取决于您使用的数据
yEnc可能适合你:
http://en.wikipedia.org/wiki/Yenc
"yEnc is a binary-to-text encoding scheme for transferring binary
files in [text]. It reduces the overhead over previous US-ASCII-based
encoding methods by using an 8-bit Extended ASCII encoding method.
yEnc's overhead is often (if each byte value appears approximately
with the same frequency on average) as little as 1–2%, compared to
33%–40% overhead for 6-bit encoding methods like uuencode and Base64.
... By 2003 yEnc became the de facto standard encoding system for
binary files on Usenet."
然而，yEnc是一种8位编码，因此将其存储在JSON字符串中与存储原始二进制数据有相同的问题-使用naïve方式意味着大约100%的展开，这比base64更糟糕。
While it is true that base64 has ~33% expansion rate, it is not necessarily true that processing overhead is significantly more than this: it really depends on JSON library/toolkit you are using. Encoding and decoding are simple straight-forward operations, and they can even be optimized wrt character encoding (as JSON only supports UTF-8/16/32) -- base64 characters are always single-byte for JSON String entries.
For example on Java platform there are libraries that can do the job rather efficiently, so that overhead is mostly due to expanded size.
我同意之前的两个答案:
base64是简单的，常用的标准，所以不太可能找到更好的标准来与JSON一起使用(base-85用于postscript等;但仔细想想，这些好处充其量只是边际的)
编码前压缩(解码后压缩)可能很有意义，这取决于您使用的数据
我也遇到了同样的问题，我想分享一个解决方案:multipart/form-data。
通过发送一个多部分的表单，你首先将你的JSON元数据作为字符串发送，然后分别以原始二进制(图像，波浪等)以Content-Disposition名称为索引发送。
这里有一个很好的教程，教你如何在obj-c中做到这一点，这里有一篇博客文章，解释了如何用表单边界划分字符串数据，并将其与二进制数据分开。
你真正需要做的唯一改变是在服务器端;你必须捕获你的元数据，它应该适当地引用POST的二进制数据(通过使用Content-Disposition边界)。
尽管这需要在服务器端进行额外的工作，但如果您要发送许多图像或大型图像，这是值得的。如果需要，可以将其与gzip压缩结合使用。
在我看来，发送base64编码的数据是一种黑客行为;RFC multipart/form-data是针对以下问题创建的:将二进制数据与文本或元数据结合发送。
