为什么新的String（bytes，enc）.getBytes（enc）不返回原始字节数组？ [英] Why new String(bytes, enc).getBytes(enc) does not return the original byte array?

问题描述

我做了以下模拟：

byte[] b = new byte[256];

for (int i = 0; i < 256; i ++) {
    b[i] = (byte) (i - 128);
}
byte[] transformed = new String(b, "cp1251").getBytes("cp1251");

for (int i = 0; i < b.length; i ++) {
    if (b[i] != transformed[i]) {
        System.out.println("Wrong : " + i);
    }
}

cp1251 这只输出一个错误的字节 - 位置25.

KOI8-R - 一切正常。

对于 cp1252 - 4或5个差异。

For cp1251 this outputs only one wrong byte - at position 25.
For KOI8-R - all fine.
For cp1252 - 4 or 5 differences.

这是什么原因以及如何克服这个？

What is the reason for this and how can this be overcome?

我知道错误将字节数组表示为任何编码的字符串，但它是支付提供商协议的要求，所以我没有选择。

I know it is wrong to represent byte arrays as strings in whatever encoding, but it is a requirement of the protocol of a payment provider, so I don't have a choice.

更新代表 ISO-8859-1 有效，我将它用于 byte [] 部分， cp1251 用于文本部分，所以问题仍然只是出于好奇

Update: representing it in ISO-8859-1 works, and I'll use it for the byte[] part, and cp1251 for the textual part, so the question remains only out of curiousity

推荐答案

目标集中不支持某些字节 - 它们是替换为？字符。转换回来时，？通常会转换为字节值63 - 这与以前不同。

Some of the "bytes" are not supported in the target set - they are replaced with the ? character. When you convert back, ? is normally converted to the byte value 63 - which isn't what it was before.

这篇关于为什么新的String（bytes，enc）.getBytes（enc）不返回原始字节数组？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！