什么是Scala方式来实现这个Java“byte [] to Hex”类
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/2756166/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
What is/are the Scala way(s) to implement this Java "byte[] to Hex" class
提问by nicerobot
I'm specifically interested in Scala (2.8) techniques for building strings with formats as well as interesting ways to make such a capability easily accessible where it's useful (lists of bytes, String, ...?)..
我对使用格式构建字符串的 Scala (2.8) 技术以及使这种功能在有用的地方（字节列表、字符串……？）轻松访问的有趣方法特别感兴趣。
public class Hex {
public static String valueOf (final byte buf[]) {
if (null == buf) {
return null;
}
final StringBuilder sb = new StringBuilder(buf.length * 2);
for (final byte b : buf) {
sb.append(String.format("%02X", b & 0xff));
}
return sb.toString();
}
public static String valueOf (final Byteable o) {
return valueOf(o.toByteArray());
}
}
This is only a learning exercise (so the utility and implementation of the Java isn't a concern.)
这只是一个学习练习（所以 Java 的实用程序和实现不是问题。）
Thanks
谢谢
采纳答案by Ben Lings
This doesn't handle nullin the same way as your code.
这null与您的代码的处理方式不同。
object Hex {
def valueOf(buf: Array[Byte]): String = buf.map("%02X" format _).mkString
def valueOf(o: Byteable): String = valueOf(o.toByteArray)
}
If you want to be able to handle possibly-nullarrays, you might be better doing that from calling code and doing:
如果您希望能够处理可能的null数组，则最好通过调用代码并执行以下操作来做到这一点：
val bytes: Array[Byte] = // something, possibly null
val string: Option[String] = Option(bytes).map(Hex.valueOf)
回答by michael.kebe
You should use Scala's Optiontype instead of null. (This is tested with Scala 2.8.0.RC1)
您应该使用 Scala 的Option类型而不是null. （这是用 Scala 2.8.0.RC1 测试的）
object Hex {
def valueOf (buf: Array[Byte]) = {
if (null == buf) {
None
} else {
val sb = new StringBuilder(buf.length * 2)
for (b <- buf) {
sb.append("%02X".format(b & 0xff))
}
Some(sb.toString())
}
}
/*
def valueOf(o: Byteable) = {
return valueOf(o.toByteArray());
}
*/
}
println(Hex.valueOf(Array(-3, -2, -1, 0, 1, 2, 3)))
println(Hex.valueOf(null))
回答by Arjan Blokzijl
Perhaps there are more elegant ways, but something like:
也许有更优雅的方式，但类似于：
def valueOf(bytes : List[Byte]) = bytes.map{
b => String.format("%02X", new java.lang.Integer(b & 0xff))
}.mkString
should work.
应该管用。
