java byte數組與int，long，short，byte轉換

 

public class DataTypeChangeHelper {/** * 將一個單位元組的byte轉換成32位的int *  * @param b *            byte * @return convert result */public static int unsignedByteToInt(byte b) {return (int) b & 0xFF;}/** * 將一個單位元組的Byte轉換成十六進位的數 *  * @param b *            byte * @return convert result */public static String byteToHex(byte b) {int i = b & 0xFF;return Integer.toHexString(i);}/** * 將一個4byte的數群組轉換成32位的int *  * @param buf *            bytes buffer * @param byte[]中開始轉換的位置 * @return convert result */public static long unsigned4BytesToInt(byte[] buf, int pos) {int firstByte = 0;int secondByte = 0;int thirdByte = 0;int fourthByte = 0;int index = pos;firstByte = (0x000000FF & ((int) buf[index]));secondByte = (0x000000FF & ((int) buf[index + 1]));thirdByte = (0x000000FF & ((int) buf[index + 2]));fourthByte = (0x000000FF & ((int) buf[index + 3]));index = index + 4;return ((long) (firstByte << 24 | secondByte << 16 | thirdByte << 8 | fourthByte)) & 0xFFFFFFFFL;}/** * 將16位的short轉換成byte數組 *  * @param s *            short * @return byte[] 長度為2 * */public static byte[] shortToByteArray(short s) {byte[] targets = new byte[2];for (int i = 0; i < 2; i++) {int offset = (targets.length - 1 - i) * 8;targets[i] = (byte) ((s >>> offset) & 0xff);}return targets;}/** * 將32位整數轉換成長度為4的byte數組 *  * @param s *            int * @return byte[] * */public static byte[] intToByteArray(int s) {byte[] targets = new byte[2];for (int i = 0; i < 4; i++) {int offset = (targets.length - 1 - i) * 8;targets[i] = (byte) ((s >>> offset) & 0xff);}return targets;}/** * long to byte[] *  * @param s *            long * @return byte[] * */public static byte[] longToByteArray(long s) {byte[] targets = new byte[2];for (int i = 0; i < 8; i++) {int offset = (targets.length - 1 - i) * 8;targets[i] = (byte) ((s >>> offset) & 0xff);}return targets;}/**32位int轉byte[]*/public static byte[] int2byte(int res) {byte[] targets = new byte[4];targets[0] = (byte) (res & 0xff);// 最低位targets[1] = (byte) ((res >> 8) & 0xff);// 次低位targets[2] = (byte) ((res >> 16) & 0xff);// 次高位targets[3] = (byte) (res >>> 24);// 最高位,無符號右移。return targets;}/** * 將長度為2的byte數群組轉換為16位int *  * @param res *            byte[] * @return int * */public static int byte2int(byte[] res) {// res = InversionByte(res);// 一個byte資料左移24位變成0x??000000，再右移8位變成0x00??0000int targets = (res[0] & 0xff) | ((res[1] << 8) & 0xff00); // | 表示安位或return targets;}}