问题
怎样快速方式将anInteger
转换成aByte Array
?
e.g.0xAABBCCDD => {AA, BB, CC, DD}
#1 热门回答(195 赞)
看看theByteBufferclass。
ByteBuffer b = ByteBuffer.allocate(4);
//b.order(ByteOrder.BIG_ENDIAN); // optional, the initial order of a byte buffer is always BIG_ENDIAN.
b.putInt(0xAABBCCDD);
byte[] result = b.array();
设置字节顺序可确保result[0] == 0xAA
,result[1] == 0xBB
,result[2] == 0xCC
和result[3] == 0xDD
。
或者,你也可以手动执行此操作:
byte[] toBytes(int i)
{
byte[] result = new byte[4];
result[0] = (byte) (i >> 24);
result[1] = (byte) (i >> 16);
result[2] = (byte) (i >> 8);
result[3] = (byte) (i /*>> 0*/);
return result;
}
尽管如此,ByteBuffer
class是为这种脏手任务而设计的。事实上,privatejava.nio.Bits
定义了ByteBuffer.putInt()
使用的这些辅助方法:
private static byte int3(int x) { return (byte)(x >> 24); }
private static byte int2(int x) { return (byte)(x >> 16); }
private static byte int1(int x) { return (byte)(x >> 8); }
private static byte int0(int x) { return (byte)(x >> 0); }
#2 热门回答(32 赞)
UsingBigInteger
:
private byte[] bigIntToByteArray( final int i ) {
BigInteger bigInt = BigInteger.valueOf(i);
return bigInt.toByteArray();
}
UsingDataOutputStream
:
private byte[] intToByteArray ( final int i ) throws IOException {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(bos);
dos.writeInt(i);
dos.flush();
return bos.toByteArray();
}
UsingByteBuffer
:
public byte[] intToBytes( final int i ) {
ByteBuffer bb = ByteBuffer.allocate(4);
bb.putInt(i);
return bb.array();
}
#3 热门回答(26 赞)
使用此功能它适用于我
public byte[] toByteArray(int value) {
return new byte[] {
(byte)(value >> 24),
(byte)(value >> 16),
(byte)(value >> 8),
(byte)value};
}
它将int转换为字节值