Java tutorial
//package com.java2s; /* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ public class Main { /** * Converts a long number to a byte array * Halfwords can be swapped by setting swapHalfWord=true. * * @param number * the input long number to be converted * * @param length * The length of the returned array * @param swapHalfWord * Swap halfwords ([0][1][2][3]->[1][0][3][2]) * @return The long value * @throws UnsupportedOperationException if the length is not a positive multiple of two */ static byte[] long2byteArray(final long number, final int length, final boolean swapHalfWord) { byte[] ret = new byte[length]; int pos = 0; long tmp_number = 0; if (length % 2 != 0 || length < 2) { throw new UnsupportedOperationException(); } tmp_number = number; for (pos = length - 1; pos >= 0; pos--) { ret[pos] = (byte) (tmp_number & 0xFF); tmp_number >>= 8; } if (!swapHalfWord) { byte tmp = 0; for (pos = 0; pos < length; pos++) { tmp = ret[pos]; ret[pos++] = ret[pos]; ret[pos] = tmp; } } return ret; } }