java中byte数组与int，long，short间的转换
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package com.util;/** * * <ul> * <li>文件名称: com.born.util.ByteUtil.java</li> * <li>文件描述: byte转换工具</li> * <li>版权所有: 版权所有(C)2001-2006</li> * <li>公 司: bran</li> * <li>内容摘要:</li> * <li>其他说明:</li> * <li>完成日期：2011-7-18</li> * <li>修改记录0：无</li> * </ul> * * @version 1.0 * @author 许力多 */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];elses += 256 + b[index + 0];s *= 256;if (b[index + 0] > 0)s += b[index + 1];elses += 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);}}?
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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??0000int targets = (res[0] & 0xff) | ((res[1] << 8) & 0xff00); // | 表示安位或return targets;}}?