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;

    }

}