package com.util; public class ByteUtil { /** * 转换short为byte * * @param b * @param s * 需要转换的short * @param index */ public static void putShort(byte b[], short s, int index) { b[index + 1] = (byte) (s >> 8); b[index + 0] = (byte) (s >> 0); } /** * 通过byte数组取到short * * @param b * @param index * 第几位开始取 * @return */ public static short getShort(byte[] b, int index) { return (short) (((b[index + 1] << 8) | b[index + 0] & 0xff)); } /** * 转换int为byte数组 * * @param bb * @param x * @param index */ public static void putInt(byte[] bb, int x, int index) { bb[index + 3] = (byte) (x >> 24); bb[index + 2] = (byte) (x >> 16); bb[index + 1] = (byte) (x >> 8); bb[index + 0] = (byte) (x >> 0); } /** * 通过byte数组取到int * * @param bb * @param index * 第几位开始 * @return */ public static int getInt(byte[] bb, int index) { return (int) ((((bb[index + 3] & 0xff) << 24) | ((bb[index + 2] & 0xff) << 16) | ((bb[index + 1] & 0xff) << 8) | ((bb[index + 0] & 0xff) << 0))); } /** * 转换long型为byte数组 * * @param bb * @param x * @param index */ public static void putLong(byte[] bb, long x, int index) { bb[index + 7] = (byte) (x >> 56); bb[index + 6] = (byte) (x >> 48); bb[index + 5] = (byte) (x >> 40); bb[index + 4] = (byte) (x >> 32); bb[index + 3] = (byte) (x >> 24); bb[index + 2] = (byte) (x >> 16); bb[index + 1] = (byte) (x >> 8); bb[index + 0] = (byte) (x >> 0); } /** * 通过byte数组取到long * * @param bb * @param index * @return */ public static long getLong(byte[] bb, int index) { return ((((long) bb[index + 7] & 0xff) << 56) | (((long) bb[index + 6] & 0xff) << 48) | (((long) bb[index + 5] & 0xff) << 40) | (((long) bb[index + 4] & 0xff) << 32) | (((long) bb[index + 3] & 0xff) << 24) | (((long) bb[index + 2] & 0xff) << 16) | (((long) bb[index + 1] & 0xff) << 8) | (((long) bb[index + 0] & 0xff) << 0)); } /** * 字符到字节转换 * * @param ch * @return */ public static void putChar(byte[] bb, char ch, int index) { int temp = (int) ch; // byte[] b = new byte[2]; for (int i = 0; i < 2; i ++ ) { bb[index + i] = new Integer(temp & 0xff).byteValue(); // 将最高位保存在最低位 temp = temp >> 8; // 向右移8位 } } /** * 字节到字符转换 * * @param b * @return */ public static char getChar(byte[] b, int index) { int s = 0; if (b[index + 1] > 0) s += b[index + 1]; else s += 256 + b[index + 0]; s *= 256; if (b[index + 0] > 0) s += b[index + 1]; else s += 256 + b[index + 0]; char ch = (char) s; return ch; } /** * float转换byte * * @param bb * @param x * @param index */ public static void putFloat(byte[] bb, float x, int index) { // byte[] b = new byte[4]; int l = Float.floatToIntBits(x); for (int i = 0; i < 4; i++) { bb[index + i] = new Integer(l).byteValue(); l = l >> 8; } } /** * 通过byte数组取得float * * @param bb * @param index * @return */ public static float getFloat(byte[] b, int index) { int l; l = b[index + 0]; l &= 0xff; l |= ((long) b[index + 1] << 8); l &= 0xffff; l |= ((long) b[index + 2] << 16); l &= 0xffffff; l |= ((long) b[index + 3] << 24); return Float.intBitsToFloat(l); } /** * double转换byte * * @param bb * @param x * @param index */ public static void putDouble(byte[] bb, double x, int index) { // byte[] b = new byte[8]; long l = Double.doubleToLongBits(x); for (int i = 0; i < 4; i++) { bb[index + i] = new Long(l).byteValue(); l = l >> 8; } } /** * 通过byte数组取得float * * @param bb * @param index * @return */ public static double getDouble(byte[] b, int index) { long l; l = b[0]; l &= 0xff; l |= ((long) b[1] << 8); l &= 0xffff; l |= ((long) b[2] << 16); l &= 0xffffff; l |= ((long) b[3] << 24); l &= 0xffffffffl; l |= ((long) b[4] << 32); l &= 0xffffffffffl; l |= ((long) b[5] << 40); l &= 0xffffffffffffl; l |= ((long) b[6] << 48); l &= 0xffffffffffffffl; l |= ((long) b[7] << 56); return Double.longBitsToDouble(l); } }
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; } }