需要帮助将字符串转换为十六进制字节

Question

I am programming in Java. The program have a String as below.

String str = "byte."

Can the above string be converted to an array of hex bytes as below?

byte[] data = {0x62, 0x79, 0x74, 0x65};

Thank you.

Answer 1

There's no such thing as "hex bytes" and more than there are "decimal integers" vs "hex integers".

You can certainly convert a string to a byte array though. For example:

byte[] data = str.getBytes("UTF-8");

The UTF-8 part here is the name of the encoding to use - where an encoding is effectively a mapping between Unicode characters and bytes. (It's somewhat more complicated than that, but it's a good first approximation.)

There is a parameterless overload of String.getBytes() but I would strongly recommend that you don't use it - it will pick the platform default encoding, which is rarely a good idea.

You can also use an overload taking a Charset , which ends up being nicer in conjunction with a library such as Guava , where you can write:

byte[] data = str.getBytes(Charsets.UTF_8);

... so you no longer rely on a string representation.