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?

Answer 1

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

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

Answer 2

using kotlin function as

charset("UTF-8")

using from your data

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

Answer 3

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.

Answer 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