在 Java 中分配给字节数组
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Assigning to a byte array in Java
提问by fredley
I have a byte array I want to assign as follows:
我有一个要分配的字节数组，如下所示：
- First byte specifies the length of the string:
(byte)string.length() - 2nd - Last bytes contain string data from
string.getBytes()
- 第一个字节指定字符串的长度：
(byte)string.length() - 第二个 - 最后一个字节包含来自
string.getBytes()
Other than using a for loop, is there a quick way to initialize a byte array using bytes from two different variables?
除了使用 for 循环之外，是否有使用来自两个不同变量的字节来初始化字节数组的快速方法？
回答by Guss
You can use System.arrayCopy()to copy your bytes:
您可以使用System.arrayCopy()复制您的字节：
String x = "xx";
byte[] out = new byte[x.getBytes().length()+1];
out[0] = (byte) (0xFF & x.getBytes().length());
System.arraycopy(x.getBytes(), 0, out, 1, x.length());
Though using something like a ByteArrayOutputStreamor a ByteBufferlike other people suggested is probably a cleaner approach and will be better for your in the long run :-)
尽管使用其他人建议的类似 aByteArrayOutputStream或ByteBuffer类似的方法可能是一种更清洁的方法，并且从长远来看对您更好:-)
回答by Anon
While ByteBufferis generally the best way to build up byte arrays, given the OP's goals I think the following will be more robust:
虽然ByteBuffer通常是构建字节数组的最佳方式，但考虑到 OP 的目标，我认为以下内容会更加健壮：
public static void main(String[] argv)
throws Exception
{
String s = "any string up to 64k long";
ByteArrayOutputStream bos = new ByteArrayOutputStream();
DataOutputStream out = new DataOutputStream(bos);
out.writeUTF(s);
out.close();
byte[] bytes = bos.toByteArray();
ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
DataInputStream in = new DataInputStream(bis);
String s2 = in.readUTF();
}
回答by Jigar Joshi
How about ByteBuffer?
怎么样ByteBuffer？
Example :
例子 ：
ByteBuffer bb = ByteBuffer.allocate(string.getBytes().length +1 );
bb.put((byte) string.length());
bb.put(string.getBytes());
回答by Brian Topping
How about ByteArrayOutputStream?
