java byte数组与int,long,short,byte的转换实现方法

public class DataTypeChangeHelper {   /**    * 将一个单字节的byte转换成32位的int    *    * @param b    *      byte    * @return convert result    */   public static int unsignedByteToInt(byte b) {     return (int) b & 0xFF;   }    /**    * 将一个单字节的Byte转换成十六进制的数    *    * @param b    *      byte    * @return convert result    */   public static String byteToHex(byte b) {     int i = b & 0xFF;     return Integer.toHexString(i);   }    /**    * 将一个4byte的数组转换成32位的int    *    * @param buf    *      bytes buffer    * @param byte[]中开始转换的位置    * @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;   }    /**    * 将16位的short转换成byte数组    *    * @param s    *      short    * @return byte[] 长度为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;   }    /**    * 将32位整数转换成长度为4的byte数组    *    * @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转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,无符号右移。     return targets;   }    /**    * 将长度为2的byte数组转换为16位int    *    * @param res    *      byte[]    * @return int    * */   public static int byte2int(byte[] res) {     // res = InversionByte(res);     // 一个byte数据左移24位变成0x??000000，再右移8位变成0x00??0000     int targets = (res[0] & 0xff) | ((res[1] << 8) & 0xff00); // | 表示安位或     return targets;   } }