long、int與byte數組之間的相互轉換

byte數組轉換成long
public long byteArrayToLong(byte[] data) throws IOException {
    ByteArrayInputStream bai = new ByteArrayInputStream(data);
    DataInputStream dis =new DataInputStream(bai);
        return dis.readLong();
}

byte數組轉換成int
public int byteArrayToInt(byte[] data) throws IOException {
    ByteArrayInputStream bai = new ByteArrayInputStream(data);
    DataInputStream dis =new DataInputStream(bai);
    return dis.readInt();
}

long轉換成byte數組
public byte[] longToByteArray(long l) throws IOException {
    ByteArrayOutputStream bao = new ByteArrayOutputStream();
    DataOutputStream dos =new DataOutputStream(bao);
    dos.writeLong(l);
    byte [] buf =bao.toByteArray();
    return buf;
}

int轉換成byte數組
public byte[] intToByteArray(int a) throws IOException {
    ByteArrayOutputStream bao = new ByteArrayOutputStream();
    DataOutputStream dos =new DataOutputStream(bao);
    dos.writeInt(a);
    byte [] buf =bao.toByteArray();
    return buf;
}