java 将 LongBuffer/IntBuffer/ShortBuffer 转换为 ByteBuffer
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/11665147/
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
convert a LongBuffer/IntBuffer/ShortBuffer to ByteBuffer
提问by logoff
I know a quick way to convert a byte/short/int/long array to ByteBuffer, and then obtain a byte array. For instance, to convert a byte array to short array I can do:
我知道一种将 byte/short/int/long 数组转换为 ByteBuffer，然后获取字节数组的快速方法。例如，要将字节数组转换为短数组，我可以执行以下操作：
byte[] bArray = { 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0 };
ByteBuffer bb = ByteBuffer.wrap(byteArray);
ShortBuffer sb = bb.asShortBuffer();
short[] shortArray = new short[byteArray.length / 2];
sb.get(shortArray);
produces a short array like this: [256, 0, 0, 0, 256, 0, 0, 0].
产生短阵列是这样的：[256, 0, 0, 0, 256, 0, 0, 0]。
How can I do the inverse operation using java.nioclasses?
如何使用java.nio类进行逆运算？
Now I am doing this:
现在我这样做：
shortArray[] = {256, 0, 0, 0, 256, 0, 0, 0};
ByteBuffer bb = ByteBuffer.allocate(shortArray.length * 2);
for (short s : shortArray) {
bb.putShort(s);
}
return bb.array();
And I obtain the original [1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0]byte array. But I want to use a method like ShortBuffer.asByteBuffer(), not a manual loop to do it.
我获得了原始的[1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0]字节数组。但我想使用像 ShortBuffer.asByteBuffer() 这样的方法，而不是手动循环来做到这一点。
I have found a request to Sun of 2001, but they did not accept it ;-((
我找到了2001 年向 Sun 提出的请求，但他们没有接受；-(
回答by A.H.
What about this? :
那这个呢？：
bb.asShortBuffer().put(shortArray);
Then bbcontains your data.
然后bb包含您的数据。
Full code:
完整代码：
public class Test {
public static void main(final String args[]) {
short[] arr = { 256, 0, 0, 0, 256, 0, 0, 0 };
for (byte b : F(arr)) {
System.out.print(b);
}
}
public static byte[] F(short[] arr) {
java.nio.ByteBuffer bb = java.nio.ByteBuffer.allocate(arr.length * 2);
bb.asShortBuffer().put(arr);
return bb.array(); // this returns the "raw" array, it's shared and not copied!
}
}
回答by Edwin Dalorzo
Well, in the declaration
嗯，在声明中
ShortBuffer sb = bb.asShortBuffer();
AFAIK, your ShortBufferis just a view of the original ByteBuffer. So, you could always access the original ByteBuffervariable bband see the data as modified through your CharBufferreference sb.
AFAIK，您ShortBuffer只是对原始ByteBuffer. 因此，您始终可以访问原始ByteBuffer变量bb并查看通过您的CharBuffer引用修改的数据sb。
The documentation for asCharBuffersays:
asCharBuffer的文档说：
[...] Changes to this buffer's content will be visible in the new buffer, and vice versa [...]
[...] 对该缓冲区内容的更改将在新缓冲区中可见，反之亦然 [...]
回答by Peter Lawrey
I would remember the ByteBuffer you used to create the ShortBuffer from as its a view onto the same buffer.
我会记得你用来创建 ShortBuffer 的 ByteBuffer 作为它对同一个缓冲区的视图。
Otherwise it appears the only way to get this back is to use reflections to get the bbfield.
否则，似乎唯一的方法是使用反射来获取bb字段。
BTW: Using a direct ByteBuffer can be significantly faster depending on what you are doing esp if you use native byte order.
顺便说一句：使用直接 ByteBuffer 可以明显更快，具体取决于您在做什么，尤其是如果您使用本机字节顺序。
