java整型数与网络字节序的 byte[] 数组转换关系

snoopy7713

工作项目需要在java和c/c++之间进行socket通信，socket通信是以字节流或者字节包进行的，socket发送方须将数据转换为字节流或者字节包，而接收方则将字节流和字节包再转换回相应的数据类型。如果发送方和接收方都是同种语言，则一般只涉及到字节序的调整。而对于java和c/c++的通信，则情况就要复杂一些，主要是因为java中没有unsigned类型，并且java和c在某些数据类型上的长度不一致。
    本文就是针对这种情况，整理了java数据类型和网络字节流或字节包(相当于java的byte数组)之间转换方法。实际上网上这方面的资料不少，但往往不全，甚至有些有错误，于是就花了点时间对java整型数和网络字节序的byte[]之间转换的各种情况做了一些验证和整理。整理出来的函数如下：


public class ByteConvert {/** * 长整形转byte数组 *  * @param n *            长整形数字 * @return 转换后的数组 */public static byte[] longToBytes(long n) {byte[] b = new byte[8];b[7] = (byte) (n & 0xff);b[6] = (byte) (n >> 8 & 0xff);b[5] = (byte) (n >> 16 & 0xff);b[4] = (byte) (n >> 24 & 0xff);b[3] = (byte) (n >> 32 & 0xff);b[2] = (byte) (n >> 40 & 0xff);b[1] = (byte) (n >> 48 & 0xff);b[0] = (byte) (n >> 56 & 0xff);return b;}/** * 长整形转byte数组 *  * @param n *            长整形数字 * @param array *            转换后的结果 * @param offset *            从第offset位开始转换 */public static void longToBytes(long n, byte[] array, int offset) {array[7 + offset] = (byte) (n & 0xff);array[6 + offset] = (byte) (n >> 8 & 0xff);array[5 + offset] = (byte) (n >> 16 & 0xff);array[4 + offset] = (byte) (n >> 24 & 0xff);array[3 + offset] = (byte) (n >> 32 & 0xff);array[2 + offset] = (byte) (n >> 40 & 0xff);array[1 + offset] = (byte) (n >> 48 & 0xff);array[0 + offset] = (byte) (n >> 56 & 0xff);}/** * bytes 转 Long *  * @param array *            要转换的byte * @return long长整形数字 */public static long bytesToLong(byte[] array) {return ((((long) array[0] & 0xff) << 56) | (((long) array[1] & 0xff) << 48) | (((long) array[2] & 0xff) << 40)        | (((long) array[3] & 0xff) << 32) | (((long) array[4] & 0xff) << 24)        | (((long) array[5] & 0xff) << 16) | (((long) array[6] & 0xff) << 8) | (((long) array[7] & 0xff) << 0));}/** * byte数组转长整形数字 *  * @param array *            要转换的byte数组 * @param offset *            从第offset开始转换 * @return 转换后的长整形数字 */public static long bytesToLong(byte[] array, int offset) {return ((((long) array[offset + 0] & 0xff) << 56) | (((long) array[offset + 1] & 0xff) << 48)        | (((long) array[offset + 2] & 0xff) << 40) | (((long) array[offset + 3] & 0xff) << 32)        | (((long) array[offset + 4] & 0xff) << 24) | (((long) array[offset + 5] & 0xff) << 16)        | (((long) array[offset + 6] & 0xff) << 8) | (((long) array[offset + 7] & 0xff) << 0));}public static byte[] intToBytes(int n) {byte[] b = new byte[4];b[3] = (byte) (n & 0xff);b[2] = (byte) (n >> 8 & 0xff);b[1] = (byte) (n >> 16 & 0xff);b[0] = (byte) (n >> 24 & 0xff);return b;}public static void intToBytes(int n, byte[] array, int offset) {array[3 + offset] = (byte) (n & 0xff);array[2 + offset] = (byte) (n >> 8 & 0xff);array[1 + offset] = (byte) (n >> 16 & 0xff);array[offset] = (byte) (n >> 24 & 0xff);}/** * @param b * @return */public static int bytesToInt(byte b[]) {return b[3] & 0xff | (b[2] & 0xff) << 8 | (b[1] & 0xff) << 16 | (b[0] & 0xff) << 24;}/** * byte 数组转 int *  * @param b *            byte数组 * @param offset *            从数组的第几位开始转 * @return 整形 */public static int bytesToInt(byte b[], int offset) {return b[offset + 3] & 0xff | (b[offset + 2] & 0xff) << 8 | (b[offset + 1] & 0xff) << 16        | (b[offset] & 0xff) << 24;}/** * 无符号整形转数组 *  * @param n *            要转换的整形 * @return byte数组 */public static byte[] uintToBytes(long n) {byte[] b = new byte[4];b[3] = (byte) (n & 0xff);b[2] = (byte) (n >> 8 & 0xff);b[1] = (byte) (n >> 16 & 0xff);b[0] = (byte) (n >> 24 & 0xff);return b;}public static void uintToBytes(long n, byte[] array, int offset) {array[3 + offset] = (byte) (n);array[2 + offset] = (byte) (n >> 8 & 0xff);array[1 + offset] = (byte) (n >> 16 & 0xff);array[offset] = (byte) (n >> 24 & 0xff);}public static long bytesToUint(byte[] array) {return ((long) (array[3] & 0xff)) | ((long) (array[2] & 0xff)) << 8 | ((long) (array[1] & 0xff)) << 16        | ((long) (array[0] & 0xff)) << 24;}public static long bytesToUint(byte[] array, int offset) {return ((long) (array[offset + 3] & 0xff)) | ((long) (array[offset + 2] & 0xff)) << 8        | ((long) (array[offset + 1] & 0xff)) << 16 | ((long) (array[offset] & 0xff)) << 24;}public static byte[] shortToBytes(short n) {byte[] b = new byte[2];b[1] = (byte) (n & 0xff);b[0] = (byte) ((n >> 8) & 0xff);return b;}public static void shortToBytes(short n, byte[] array, int offset) {array[offset + 1] = (byte) (n & 0xff);array[offset] = (byte) ((n >> 8) & 0xff);}public static short bytesToShort(byte[] b) {return (short) (b[1] & 0xff | (b[0] & 0xff) << 8);}public static short bytesToShort(byte[] b, int offset) {return (short) (b[offset + 1] & 0xff | (b[offset] & 0xff) << 8);}public static byte[] ushortToBytes(int n) {byte[] b = new byte[2];b[1] = (byte) (n & 0xff);b[0] = (byte) ((n >> 8) & 0xff);return b;}public static void ushortToBytes(int n, byte[] array, int offset) {array[offset + 1] = (byte) (n & 0xff);array[offset] = (byte) ((n >> 8) & 0xff);}public static int bytesToUshort(byte b[]) {return b[1] & 0xff | (b[0] & 0xff) << 8;}public static int bytesToUshort(byte b[], int offset) {return b[offset + 1] & 0xff | (b[offset] & 0xff) << 8;}public static byte[] ubyteToBytes(int n) {byte[] b = new byte[1];b[0] = (byte) (n & 0xff);return b;}public static void ubyteToBytes(int n, byte[] array, int offset) {array[0] = (byte) (n & 0xff);}public static int bytesToUbyte(byte[] array) {return array[0] & 0xff;}public static int bytesToUbyte(byte[] array, int offset) {return array[offset] & 0xff;}// char 类型、 float、double 类型和 byte[] 数组之间的转换关系还需继续研究实现。}