【工具类】Java常用数据类型的转换

/** * @declaration 常用数据类型转换  * @date 2012-10-30 下午2:44:25  * */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 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 & (buf[index]));secondByte = (0x000000FF & (buf[index + 1]));thirdByte = (0x000000FF & (buf[index + 2]));fourthByte = (0x000000FF & (buf[index + 3]));index = index + 4;return (firstByte << 24 | secondByte << 16 | thirdByte << 8 | fourthByte) & 0xFFFFFFFFL;}/** * 将一个byte的数组转换成short数组 * @param buf 数据 * @param size 数据大小 * @return */public short[] byteAryToShortAry(byte [] buf, int size){int arySize = size / 2;short [] result = new short[arySize];int firstByte = 0;int secondByte = 0;for (int i = 0; i < arySize; i+=2){firstByte = (0x000000FF & (buf[i]));secondByte = (0x000000FF & (buf[i + 1]));result[i] = (short)((firstByte << 8 | secondByte) & 0xffff);}return result;}/** * 将一个short的数组转换成byte数组 * @param buf * @param size * @return */public byte[] shortAryToByteAry(short [] buf, int size){int arySize = size * 2;byte [] result = new byte[arySize];for (int i = 0; i < arySize; i+=2){result[i] = (byte)(0xFF & (buf[i/2]>>8));result[i+1] = (byte)(0xFF & (buf[i/2]));}return result;}/** * 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;}}