Encode String to UTF-8 in Kotlin

Question

Often times when dealing with json and responses you want to encode String to UTF-8 in java.

String response = new String(response.data, UTF); // java code

For Kotlin, how is this done? I converted my Java class and the result was

String response = String(response.data, UTF) // kotlin code

But this results in an error, because I believe the Kotlin String() method is different than what I am doing in Java. Is it as simple as using the toString()?

String response = response.data.toString() // kotlin code

How does the system know to use UTF-8, or is that just the default? This is just hypothetical, but what if I wanted to do something with String object and therefore used UTF-16? How can I change the encoding?

Solution 1

Kotlin has an overload of ByteArray.toString accepting a Charset. All you need to do is use it: array.toString(charset).

I cannot find a section in the documentation specifying that ByteArray.toString() does the right thing, as it doesn't in Java and that behavior probably is preserved in Kotlin. I would guess it does the wrong thing. I recommend using toString(charset) explicitly.

Solution 2

You can try this String(data, Charsets.UTF_8)

Reference : https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/to-string.html

Solution 3

using kotlin function as

charset("UTF-8")

using from your data

 String(response.data, charset("UTF-8"))

Solution 4

Kotlin 1.3.40 provides an experimental common ByteArray.decodeToString function.

It takes a ByteArray containing bytes of string encoded with utf8 encoding and decodes it to kotlin String. So you can use it like:

String response = response.data.decodeToString()

Note that using this function requires to opt in for the experimental stdlib API. You can learn more about the supported ways to make this opt-in here: https://kotlinlang.org/docs/reference/experimental.html

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Comments

[portfoliobuilder]

I see, simple. Kotlin makes things simpler seems like. Just need to learn more about the language. Thanks for your answer, I will try it.

[Gavin]

ByteArray.stringFromUtf8 seems to be only available for native code?

[portfoliobuilder]

Do you think this is the better way to go? Presumably, this would mean that ByteArray,decodeToString() will be the new way to doing things and ByteArray.toString() may be deprecated (or not supported), right?

[Shujat Munawar]

Thanks man, this should be accepted answer, Simple, easy and well defined Thanks again