Android开发中十六进制字符串的各种转换

在我们进行开发中，会遇到将16进制转换为各种形式，今天我们就详细的讲解一下：

1、十六进制字符串转byte[]

public static byte[] hexStringToBytes(String hexString) {
    if (hexString == null || hexString.equals("")) {
        return null;
    }
    hexString = hexString.trim();
    hexString = hexString.toUpperCase();
    int length = hexString.length() / 2;
    char[] hexChars = hexString.toCharArray();
    byte[] d = new byte[length];
    for (int i = 0; i < length; i++) {
        int pos = i * 2;
        d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));
    }
    return d;
}

public static byte charToByte(char c) {
    return (byte) "0123456789ABCDEF".indexOf(c);
}

2、byte[]转十六进制字符串

public static String bytesToHexString(byte[] b) {
    if (b.length == 0) {
        return null;
    }
    StringBuilder sb = new StringBuilder();
    for (byte item : b) {
        int value = item & 0xFF;
        String hv = Integer.toHexString(value);
        if (hv.length() < 2) {
            sb.append(0);
        }

        sb.append(hv);
    }
    return sb.toString();
}

3、十六进制字符串 高低位转换

public static String reverseHex(String hex) {
    char[] charArray = hex.toCharArray();
    int length = charArray.length;
    int times = length / 2;
    for (int c1i = 0; c1i < times; c1i += 2) {
        int c2i = c1i + 1;
        char c1 = charArray[c1i];
        char c2 = charArray[c2i];
        int c3i = length - c1i - 2;
        int c4i = length - c1i - 1;
        charArray[c1i] = charArray[c3i];
        charArray[c2i] = charArray[c4i];
        charArray[c3i] = c1;
        charArray[c4i] = c2;
    }
    return new String(charArray);
}

4、十六进制字符串转换为float符点型

public static long parseLong(String s, int radix) throws NumberFormatException {
    if (s == null) {
        throw new NumberFormatException("null");
    }
    if (radix < Character.MIN_RADIX) {
        throw new NumberFormatException("radix" + radix + "less than Character.MIN_RADIX");
    }
    if (radix > Character.MAX_RADIX) {
        throw new NumberFormatException("radix" + radix + "greater than Character.MAX_RADIX");
    }
    long result = 0;
    boolean negative = false;
    int i = 0, len = s.length();
    long limit = -Long.MAX_VALUE;
    long multmin;
    int digit;
    if (len > 0) {
        char firstChar = s.charAt(0);
        if (firstChar < '0') {// Possible leading "+" or "-"
            if (firstChar == '-') {
                negative = true;
                limit = Long.MIN_VALUE;
            } else if (firstChar != '+')
                throw NumberFormatException.forlnputString(s);
            if (len == 1) // Cannot have lone "+" or "-"
                throw NumberFormatException.forlnputString(s);
            i++;
        }
        multmin = limit / radix;
        while (i < len) {
            // Accumulating negatively avoids surprises near MAX_VALUE
            digit = Character.digit(s.charAt(i++), radix);
            if (digit < 0) {
                throw NumberFormatException.forlnputString(s);
            }
            if (result < multmin) {
                throw NumberFormatException.forlnputString(s);
            }
            result *= radix;
            if (result < limit + digit) {
                throw NumberFormatException.forlnputString(s);
            }
            result -= digit;
        }
    } else {
        throw NumberFormatException.forlnputString(s);
    }
    return negative ? result : -result;
}

/**
 * NuberFormatException
 */
public static class NumberFormatException extends IllegalAccessException {
    /**
     *
     */
    private static final long serialVersionUID = 1L;

    public NumberFormatException(String s) {
        super(s);
    }

    static NumberFormatException forlnputString(String s) {
        return new NumberFormatException("For input string: \"" + s + "\"");
    }
}

以上就是讲解的主要的转换方式，以供大家参考。