Java 8中basic和url base64编码之间的区别 [英] Difference between basic and url base64 encoding in Java 8

问题描述

Java 8 Base64 库有两个可用于URI构建的变体：基本和URL和文件名安全。该文档指向 RFC 4648 表2作为差异的解释。

The Java 8 Base64 library has two variants that can be used in URI building: the "Basic" one and the "URL and Filename safe". The documentation points to RFC 4648 Table 2 as an explanation for the differences.

在阅读规范之后，我仍然不清楚两种编码之间的实际差异：两种标准都得到广泛支持吗？具体的浏览器呢？是否建议对数据URI编码使用URL和文件名安全编码？是否有已知的支持限制？

After reading the spec it still isn't clear to me what the practical difference is between both encodings: are both standards "widely" supported? What about browsers specifically? Is the URL and filename safe encoding recommended for data URI encoding? Are there known support limitations?

推荐答案

最简单的方法是提供一个示例（恕我直言）：

The easiest way is to provide an example(IMHO):

    Base64.Encoder enc = Base64.getEncoder();
    Base64.Encoder encURL = Base64.getUrlEncoder();

    byte[] bytes = enc.encode("subjects?_d".getBytes());
    byte[] bytesURL = encURL.encode("subjects?_d".getBytes());

    System.out.println(new String(bytes)); // c3ViamVjdHM/X2Q=      notice the "/"
    System.out.println(new String(bytesURL)); // c3ViamVjdHM_X2Q=   notice the "_"

    Base64.Decoder dec = Base64.getDecoder();
    Base64.Decoder decURL = Base64.getUrlDecoder();

    byte[] decodedURL = decURL.decode(bytesURL);
    byte[] decoded = dec.decode(bytes);

    System.out.println(new String(decodedURL));
    System.out.println(new String(decoded));

注意一个 URL安全和其他不是。

事实上，如果你看一下实现，有两个用于编码的查找表： toBase64 和 toBase64URL 。只有两个字符不同：

As a matter of fact if you look at the implementation, there are two look-up tables used for encoding: toBase64 and toBase64URL. There are two characters only that differ for them:

+ 和 / for toBase64 与 - 和 _ for toBase64URL 。

+ and / for toBase64 versus - and _ for toBase64URL.

所以看来你的问题是一个安全的URI，应该在那里使用吗？ / em>的;答案是肯定的。

So it seems that your question is one URI safe and should be used there?; the answer is yes.

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