Java 字节数组到字符串到字节数组 [英] Java Byte Array to String to Byte Array

问题描述

我试图理解字节[]到字符串，字节[]到字节[]转换的字符串表示......我将我的字节[]转换为要发送的字符串，然后我期望我的网络服务(写在 python 中)将数据直接回显给客户端.

I'm trying to understand a byte[] to string, string representation of byte[] to byte[] conversion... I convert my byte[] to a string to send, I then expect my web service (written in python) to echo the data straight back to the client.

当我从 Java 应用程序发送数据时...

When I send the data from my Java application...

Arrays.toString(data.toByteArray())

要发送的字节数..

[B@405217f8

发送(这是 Arrays.toString() 的结果，它应该是我的字节数据的字符串表示，该数据将通过网络发送):

Send (This is the result of Arrays.toString() which should be a string representation of my byte data, this data will be sent across the wire):

[-47, 1, 16, 84, 2, 101, 110, 83, 111, 109, 101, 32, 78, 70, 67, 32, 68, 97, 116, 97]

在python端，python服务器向调用者返回一个字符串(我可以看到和我发送给服务器的字符串相同

On the python side, the python server returns a string to the caller (which I can see is the same as the string I sent to the server

[-47, 1, 16, 84, 2, 101, 110, 83, 111, 109, 101, 32, 78, 70, 67, 32, 68, 97, 116, 97]

服务器应该将此数据返回给客户端，在那里可以对其进行验证.

The server should return this data to the client, where it can be verified.

我的客户收到的响应(作为字符串)看起来像

The response my client receives (as a string) looks like

[-47, 1, 16, 84, 2, 101, 110, 83, 111, 109, 101, 32, 78, 70, 67, 32, 68, 97, 116, 97]

我似乎无法弄清楚如何将接收到的字符串重新转换为字节[]

I can't seem to figure out how to get the received string back into a byte[]

无论我似乎尝试什么，我最终都会得到一个字节数组，如下所示......

Whatever I seem to try I end up getting a byte array which looks as follows...

[91, 45, 52, 55, 44, 32, 49, 44, 32, 49, 54, 44, 32, 56, 52, 44, 32, 50, 44, 32, 49, 48, 49, 44, 32, 49, 49, 48, 44, 32, 56, 51, 44, 32, 49, 49, 49, 44, 32, 49, 48, 57, 44, 32, 49, 48, 49, 44, 32, 51, 50, 44, 32, 55, 56, 44, 32, 55, 48, 44, 32, 54, 55, 44, 32, 51, 50, 44, 32, 54, 56, 44, 32, 57, 55, 44, 32, 49, 49, 54, 44, 32, 57, 55, 93]

或者我可以得到如下的字节表示:

or I can get a byte representation which is as follows:

B@2a80d889

这两个都与我发送的数据不同......我确定我遗漏了一些真正简单的东西......

Both of these are different from my sent data... I'm sure Im missing something truly simple....

有什么帮助吗?！

推荐答案

你不能只获取返回的字符串并从中构造一个字符串...它不是 byte[] 数据类型不再，它已经是一个字符串；你需要解析它.例如:

You can't just take the returned string and construct a string from it... it's not a byte[] data type anymore, it's already a string; you need to parse it. For example :

String response = "[-47, 1, 16, 84, 2, 101, 110, 83, 111, 109, 101, 32, 78, 70, 67, 32, 68, 97, 116, 97]";      // response from the Python script

String[] byteValues = response.substring(1, response.length() - 1).split(",");
byte[] bytes = new byte[byteValues.length];

for (int i=0, len=bytes.length; i<len; i++) {
   bytes[i] = Byte.parseByte(byteValues[i].trim());     
}

String str = new String(bytes);

** 编辑 **

你在你的问题中得到了一个提示，你说无论我尝试什么，我最终都会得到一个字节数组，如下所示...... [91, 45, ..."，因为91是[的字节值，所以[91, 45, ...就是字符串的字节数组"[-45, 1, 16, ..." 字符串.

You get an hint of your problem in your question, where you say "Whatever I seem to try I end up getting a byte array which looks as follows... [91, 45, ...", because 91 is the byte value for [, so [91, 45, ... is the byte array of the string "[-45, 1, 16, ..." string.

方法Arrays.toString() 将返回指定数组的String 表示；这意味着返回的值将不再是数组.例如:

The method Arrays.toString() will return a String representation of the specified array; meaning that the returned value will not be a array anymore. For example :

byte[] b1 = new byte[] {97, 98, 99};

String s1 = Arrays.toString(b1);
String s2 = new String(b1);

System.out.println(s1);        // -> "[97, 98, 99]"
System.out.println(s2);        // -> "abc";

如您所见，s1 保存了 array b1 的字符串表示，而 s2 保存了b1 中包含的字节的字符串表示.

As you can see, s1 holds the string representation of the array b1, while s2 holds the string representation of the bytes contained in b1.

现在，在您的问题中，您的服务器返回一个类似于 s1 的字符串，因此要返回数组表示，您需要相反的构造函数方法.如果s2.getBytes()与new String(b1)相反，则需要找到Arrays.toString(b1)的相反数，因此我粘贴在这个答案的第一个片段中的代码.

Now, in your problem, your server returns a string similar to s1, therefore to get the array representation back, you need the opposite constructor method. If s2.getBytes() is the opposite of new String(b1), you need to find the opposite of Arrays.toString(b1), thus the code I pasted in the first snippet of this answer.

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