RadixUtil-处理进制的工具类

package main;import java.util.HashMap;import java.util.Map;/** * 处理进制的工具类 **/public class RadixUtil {    private final static String NAME = RadixUtil.class.getName();    /**     * 产生进制的数字     **/    public final static char[] DIGIT = {//            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', //            'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', //            'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', //            'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', //            'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', //            'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', //            '8', '9' //    };    public final static Map<Character, Integer> digitMap = new HashMap<Character, Integer>();    static {        for (int i = 0; i < DIGIT.length; i++) {            digitMap.put(Character.valueOf(DIGIT[i]), Integer.valueOf(i));        }    }    /**     * 支持的最大进制数     */    public static final int MAX_RADIX = DIGIT.length;    /**     * 支持的最小进制数     */    public static final int MIN_RADIX = 2;    /**     * 最多一次返回32个字符     **/    public static final int SIZE = 32;    /**     * 获得0的个数     **/    public static String obtainZero(int num) {        return obtainChar(num, DIGIT[0]);    }    /**     * 获得0的个数     **/    public static String obtainZero0(int num) {        return obtainChar(num, '0');    }    /**     * 获得特殊字符的个数     **/    public static String obtainChar(int num, char c) {        if (num < 0) {            return "";        }        StringBuilder sb = new StringBuilder();        while (num-- > 0) {            sb.append(c);        }        return sb.toString();    }    /**     * 获得long型数据的最大长度     **/    public static int obtainMaxLengOfLong() {        return longToString(Long.MAX_VALUE).length();    }    /**     * 只用26个大写字母     **/    public static String longToLetter(long i) {        return longToString(i, 26);    }    public static String longToString(long i) {        return longToString(i, MAX_RADIX);    }    /**     * 将长整型数值转换为指定的进制数（最大支持62进制）     */    public static String longToString(long i, int radix) {        if (radix < MIN_RADIX || radix > MAX_RADIX) {            radix = 10;        }        if (radix == 10) {            return Long.toString(i);        }        StringBuilder sb = new StringBuilder(SIZE);        boolean negative = (i < 0);        if (negative) {            i = -i;        }        while (i >= radix) {            sb.append(DIGIT[(int) (i % radix)]);            i = i / radix;        }        sb.append(DIGIT[(int) (i)]);        if (negative) {            sb.append("-");        }        return sb.reverse().toString();    }    /**     * 将字符串转换为长整型数字     */    public static long stringToLong(String s) {        return stringToLong(s, MAX_RADIX);    }    public static long letterToLong(String s) {        return stringToLong(s, 26);    }    /**     * 将字符串转换为长整型数字     */    public static long stringToLong(String s, int radix) {        if (s == null) {            throw new NumberFormatException("null");        }        if (radix < MIN_RADIX) {            throw new NumberFormatException("radix " + radix + " less than " + NAME + ".MIN_RADIX");        }        if (radix > MAX_RADIX) {            throw new NumberFormatException("radix " + radix + " greater than " + NAME + ".MAX_RADIX");        }        // 返回结果        long result = 0;        char[] ss = s.toCharArray();        // 计算阶乘        long factorial = 1;        for (int i = (ss.length - 1); i >= 0; i--) {            char c = ss[i];            Integer v = digitMap.get(Character.valueOf(c));            if (v != null) {                result += v.intValue() * factorial;                factorial *= radix;            } else if (c == '-') {                result = -result;            } else {                throw new NumberFormatException("char " + c + " not in " + NAME + ".DIGIT");            }        }        return result;    }    public static byte[] stringToBytes(String s) {        return stringToBytes(s, MAX_RADIX);    }    /**     * 将string转换成byte数组     */    public static byte[] stringToBytes(String s, int radix) {        if (s == null) {            throw new NullPointerException(NAME + "parameter s is null");        }        // 二进制的数组        StringBuilder binary = new StringBuilder(s.getBytes().length * 8);        long t;        String te = null;        // 定长,照着这个长度切割        int llength = obtainMaxLengOfLong();        // 长度        // 最后一位是标记，最后一段的长度的        int length = s.length() - 1;        // 最后一段的长度        int lastLength = (int) stringToLong(s.substring(length, s.length()), radix);        // 下标        int start = 0;        int end = llength;        while (end < length) {            // 转换成long            t = stringToLong(s.substring(start, end), radix);            // 转换成二进制string            te = Long.toBinaryString(t);            // 补齐0            te = obtainZero0(radix - te.length()) + te;            binary.append(te);            start = end;            end = start + llength;        }        // 最后一段        if (start < length) {            t = stringToLong(s.substring(start, length), radix);            te = Long.toBinaryString(t);            te = obtainZero0(lastLength - te.length()) + te;            binary.append(te);        }        System.out.println("binary.toString()");        System.out.println(binary.toString());        // 将二进制转换成byte数据        // 返回的结果        length = binary.length();        byte[] result = new byte[length / Byte.SIZE];        int i = 0;        start = 0;        end = Byte.SIZE;        while (end < length) {            result[i++] = parseByte(binary.substring(start, end), 2);            start = end;            end = start + Byte.SIZE;        }        // 最后一段        if (start < length) {            result[i++] = parseByte(binary.substring(start, length), 2);        }        return result;    }    public static String bytesToString(byte[] bs) {        return bytesToString(bs, MAX_RADIX);    }    /**     * 将byte数组转换成string     */    public static String bytesToString(byte[] bs, int radix) {        // 最终的结果        StringBuilder result = new StringBuilder(bs.length);        // 二进制的数组        StringBuilder binary = new StringBuilder(bs.length * 8);        // 临时存储        String t = null;        for (int n = 0; n < bs.length; n++) {            byte b = bs[n];            // 将byte转化成 二进制的string            t = Integer.toBinaryString(Byte.toUnsignedInt(b));            // 获得完成8位的二进制的string            binary.append(obtainZero0(Byte.SIZE - t.length()) + t);        }        System.out.println("binary.toString()");        System.out.println(binary.toString());        // 长度        int length = binary.length();        // 下标        int start = 0;        int end = radix;        while (end < length) {            t = longToString(Long.valueOf(binary.substring(start, end), 2), radix);            result.append(obtainZero(obtainMaxLengOfLong() - t.length()) + t);            start = end;            end = start + radix;        }        // 最后不必设置成定长        if (start < length) {            t = longToString(Long.valueOf(binary.substring(start, length), 2), radix);            result.append(t);            result.append(longToString(length - start, radix));        } else {            result.append(longToString(0, radix));        }        return result.toString();    }    public static byte parseByte(String s, int radix) throws NumberFormatException {        if (s == null) {            throw new NumberFormatException("s is null");        }        if (s.length() < 8) {            return Byte.parseByte(s, radix);        }        boolean nagetive = false;        if (s.charAt(0) == '1') {            s = '0' + s.substring(1, s.length());            nagetive = true;        }        int i = Integer.parseInt(s, radix);        if (nagetive) {            i = -i;        }        if (i < Byte.MIN_VALUE || i > Byte.MAX_VALUE)            throw new NumberFormatException("Value out of range. Value:\"" + s + "\" Radix:" + radix);        return (byte) i;    }    public static void main(String[] args) {        long a = 123456789L;        System.out.println(a);        String s = longToLetter(a);        System.out.println(s);        long b = letterToLong(s);        System.out.println(b);    }}