Java字节转换类实现
Java的类库支持完全不如C#，比如时间类，比如数据类型转换类等等，难道是我自己没找到吗？
下面是字节转换类，byte[]与short, int, long, float, double, String相互转换；网络字节序htons, htonl等实现；byte[]转十六进制字符串、二进制字符串实现。
希望对朋友有用，如果有更好的方法，请提醒我。
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 < 8; i++) { bb[index + i] = new Long(l).byteValue(); l = l >> 8; } } /** * 通过byte数组取得double * * @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 static void putHexString(byte[] bb, String s, int index){ for (int i = 0; i < s.length(); i+=2) { byte c= (byte)( charToByte(s.charAt(i))<<4 | charToByte(s.charAt(i+1))); bb[index+(i>>1)] = c; } } private static byte charToByte(char c) { return (byte) "0123456789ABCDEF".indexOf(c); } public static String getHexString(byte[] b, int index, int count){ StringBuilder stringBuilder = new StringBuilder(""); if (b == null || index < 0 || b.length < index + count ) { return null; } for (int i = index; i < count + index; i++) { int v = b[i] & 0xFF; String hv = Integer.toHexString(v); if (hv.length() < 2) { stringBuilder.append(0); } stringBuilder.append(hv); } return stringBuilder.toString(); } public static String getBinaryString(int d,int length){ StringBuilder stringBuilder = new StringBuilder(""); String hv = Integer.toBinaryString(d); for (int j = 0; j < length - hv.length(); j++) { stringBuilder.append(0); } stringBuilder.append(hv); return stringBuilder.toString(); } public static String getBinaryReverseString(int d,int length){ StringBuilder stringBuilder = new StringBuilder(""); String hv = Integer.toBinaryString(d); for (int j = 0; j < length - hv.length(); j++) { stringBuilder.append(0); } stringBuilder.append(hv); stringBuilder.reverse(); return stringBuilder.toString(); } //网络字节逆序 public static byte[] ReversEndian(byte b[],int count, boolean big) { byte by; byte data[] = new byte[count]; for(int i=0;i<count;i++) { data[i] = b[i]; } if(big==false) { for(int i=0;i<count;i++) { by = b[i]; data[count-i-1] = by; } } return data; } public static short htons(short s){ short rslt = 0; byte [] bs1 = new byte[2]; ByteUtil.putShort(bs1, s, 0); byte[] bs2 = ReversEndian(bs1, 2, false); rslt = ByteUtil.getShort(bs2, 0); return rslt; } public static int htonl(int d){ int rslt = 0; byte [] bs1 = new byte[4]; ByteUtil.putInt(bs1, d, 0); byte[] bs2 = ReversEndian(bs1, 4, false); rslt = ByteUtil.getInt(bs2, 0); return rslt; } }
