[英]How can I convert Stream<Byte> to InputStream
I have java.util.stream.Stream<Byte>
in Java/Kotlin(jvm).我在 Java/Kotlin(jvm) 中有
java.util.stream.Stream<Byte>
。
How can I convert java.util.stream.Stream<Byte>
to java.io.InputStream
without keeping each buffer in memory.如何将
java.util.stream.Stream<Byte>
转换为java.io.InputStream
而不将每个缓冲区保留在内存中。
I can do this conversion by我可以通过
val inputStream = ByteArrayInputStream(byteStream.collect(Collectors.toList()).toByteArray())
But it will create a large byte[]/ByteArray in memory if the stream is very long.但是如果流很长,它会在内存中创建一个大的 byte[]/ByteArray 。
You could implement it with something like this:你可以用这样的东西来实现它:
fun main() {
val stream = Stream.of<Byte>(10, 15, -50, 20, 50)
val buf = ByteArrayOutputStream()
stream.asInputStream().transferTo(buf)
val bytes = buf.toByteArray() // [10, 15, -50, 20, 50]
}
fun Stream<Byte>.asInputStream() = object : InputStream() {
private val iter = iterator()
override fun read() = if (iter.hasNext()) iter.next().toUByte().toInt() else -1
}
You would probably need to override more methods to improve performance or provide more functionality, like for example closing the stream.您可能需要覆盖更多方法以提高性能或提供更多功能,例如关闭流。
Also, note that I didn't test this code thoroughly.另外,请注意,我没有彻底测试此代码。
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