byte与其他基本数据类型转换

傷城~ 2022-06-09 23:49 239阅读 0赞

自己从百度上零零散散整的项目的工具类，不多说，直接贴代码，有问题的，望指教

private static ByteBuffer buffer = ByteBuffer.allocate(8);
    
        /* byte字节数组转double */
        public static Double getDouble(byte[] temp) {
            long value = 0;
            for (int i = 0; i < temp.length; i++) {
                value |= ((long) (temp[i] & 0xff)) << (8 * i);
            }
            double d = Double.longBitsToDouble(value);
            return d;
        }
    
        /* double转byte字节数组 */
        public static byte[] putDouble(byte[] arr, double number, int index) {
            int len = index - 1;
            int arrLen = arr.length;
            boolean b = isOutOfArrLength(arrLen, len); // 判断当前数组长度是否大于转换的数组长度
            Long l = Double.doubleToLongBits(number);
            if (b) {
                for (int i = 0; i <= 7; i++) {
                    arr[i] = l.byteValue();
                    l = l >> 8;
                }
            } else {
                // 如果当前数组长度小于转换的数组长度，就根据index截取转换的数组元素
                l = l >> (8 * index);
                for (int j = arrLen - index - 1; j >= 0; j--) {
                    arr[j] = l.byteValue();
                    l = l >> 8;
                }
            }
    // for (byte c : arr) { 
    // System.out.println("c--->" + c);
    // }
            return arr;
        }
    
        public static boolean isOutOfArrLength(int arrLength, int index) {
            boolean b;
            if (arrLength > index) {
                b = true;
            } else {
                b = false;
            }
            return b;
        }
    
        /* 16进制转二进制 */
        public static String convertHexToBinary3(String hexString) {
            long l = Long.parseLong(hexString, 16);
            String binaryString = Long.toBinaryString(l);
            // int shouldBinaryLen = hexString.length() * 4;
            StringBuffer addZero = new StringBuffer();
            // int addZeroNum = shouldBinaryLen - binaryString.length();
            /* * for (int i = 1; i <= addZeroNum; i++) { addZero.append("0"); } */
            return addZero.toString() + binaryString;
        }
    
        /* 二进制转10进制 */
        public static int er(int s) {
            int sum = 0;
            int i = 0;
            while (s != 0) {
                sum = (int) (sum + s % 10 * (Math.pow(2, i)));
                s = s / 10;
                i++;
            }
            return sum;
        }
    
        /* 10转成16进制 */
        public static String shi(String str) {
            StringBuffer sb = new StringBuffer(str.length());
            String tmp = null;
            for (int i = 0; i < str.length(); i = i + 2) {
                tmp = str.substring(i, i + 2);
                String strtmp = Integer.toHexString(Integer.parseInt(tmp));
                sb.append(strtmp);
            }
            // System.out.println(sb.toString());
            return sb.toString();
        }
    
        /* 16进制转成10进制 */
        public static void main(String[] args) {
            long l = 12340006;
            byte[] bytes = Conversion.longToBytes(l);
            for (byte aByte : bytes) {
                System.out.println(aByte);
            }
        }
    
        /* int转byte[] */
        public static byte[] intToBytes(int value) {
            byte[] bytes = new byte[4];
            bytes[3] = (byte) (value >> 24);
            bytes[2] = (byte) (value >> 16);
            bytes[1] = (byte) (value >> 8);
            bytes[0] = (byte) (value >> 0);
            return bytes;
        }
    
        /* short转byte[] */
        public static byte[] shortToByte(short value) {
            byte[] bytes = new byte[2];
            bytes[1] = (byte) (value >> 8);
            bytes[0] = (byte) (value >> 0);
            return bytes;
        }
    
        /* byte转16进制 */
        public static String byteToHex(byte b) {
            int i = b & 0xFF;
            return Integer.toHexString(i);
        }
    
        /* byte[]转int */
        public static int bytesToInt(byte[] bytes) {
            return (int) ((((bytes[3] & 0xff) << 24)
                    | ((bytes[2] & 0xff) << 16)
                    | ((bytes[1] & 0xff) << 8) | ((bytes[0] & 0xff) << 0)));
        }
    
        /* byte[]转short */
        public static short bytesToShort(byte[] bytes) {
            return (short) (((bytes[1] << 8) | bytes[0] & 0xff));
        }
    
        /* byte 数组与 long 的相互转换 */
        public static byte[] longToBytes(long x) {
          /* buffer.putLong(0, x); buffer.flip();//need flip return buffer.array();*/
            byte[] b = new byte[8];
            for (int i = 0; i < b.length; i++) {
                b[i] = new Long(x & 0xff).byteValue();//
                x = x >> 8; // 向右移8位
            }
            return b;
        }
    
        public static long bytesToLong(byte[] bytes) {
            buffer.put(bytes, 0, bytes.length);
            buffer.flip();//need flip
            return buffer.getLong();
        }