Java和C/C++交互的字节工具类

 package cn.com.insigma.utils;import java.util.Calendar;import java.util.Date;/** * 字节工具类 * @author jingxuan */public class ByteUtils {/*** int convert byte[]* @param n* @return*/public static byte[] int2Bytes(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; }/*** byte[] convert int* @param b* @return*/public static int bytes2Int(byte b[]) {return b[3] & 0xff | (b[2] & 0xff) << 8 | (b[1] & 0xff) << 16| (b[0] & 0xff) << 24;}/*** float to byte[]* @param f* @return*/public static byte[] float2Bytes(float f) {int fbit = Float.floatToIntBits(f);byte[] b = new byte[4];for (int i = 0; i < 4; i++) {b[i] = (byte) (fbit >> (24 - i * 8));}int len = b.length;byte[] dest = new byte[len];System.arraycopy(b, 0, dest, 0, len);byte temp;for (int i = 0; i < len / 2; ++i) {temp = dest[i];dest[i] = dest[len - i - 1];dest[len - i - 1] = temp;}return dest;}// 时1字节，分1字节，秒1字节，年2字节，月1字节，日1字节, 预留1字节/*** 日期转成8字节byte[]* @param date* @return*/public static byte[] date2Bytes(Date date) {byte[] b = new byte[8];Calendar cal = Calendar.getInstance();cal.setTime(date);int year = cal.get(Calendar.YEAR);int month = cal.get(Calendar.MONTH);int day = cal.get(Calendar.DAY_OF_MONTH);int hour = cal.get(Calendar.HOUR_OF_DAY);int minute = cal.get(Calendar.MINUTE);int second = cal.get(Calendar.SECOND);// 按时、分、秒、年、月、日顺序b[0] = int2OneByte(hour); // 1字节b[1] = int2OneByte(minute);// 1字节b[2] = int2OneByte(second);// 1字节System.arraycopy(int2TwoBytes(year), 0, b, 3, 2);// 年，2字节b[5] = int2OneByte(month+1);// 1字节b[6] = int2OneByte(day);// 1字节//b[7] 保留一字节return b;}public static long bytes2Long(byte[] b)  {        long iOutcome = 0;        byte bLoop;        for (int i = 0; i <b.length; i++)  {            bLoop = b[i];           iOutcome += ((long)(bLoop & 0x000000ff)) << (8 * i);        }        return iOutcome;    } public static byte[] longtoBytes(long l){byte[] byteArray = new byte[8];        for (int i=0; i<8; i++){            byteArray[i] = new Long(l & 0xFF).byteValue();            l >>= 8;        }            return byteArray;    }/*** int convert 1 byte* @param num* @return*/public static byte int2OneByte(int num) {return (byte) (num & 0xff);}/*** int convert byte[](length = 2)* @param num* @return*/public static byte[] int2TwoBytes(int num) {byte[] b = new byte[2];b[1] = (byte) (num & 0xff);b[0] = (byte) (num >> 8 & 0xff);return b;}/*** short convert byte[]* @param b* @return*/public static short bytes2Short(byte[] b){return (short)(b[1] & 0xff | (b[0] & 0xff) << 8);}}