这是我的长到压缩十进制方法的版本。
public class PackedDecimal { public static byte[] format(long number, int bytes) { byte[] b = new byte[bytes]; final byte minusSign = 0x0D; // Minus final byte noSign = 0x0F; // Unsigned String s = Long.toString(number); int length = s.length(); boolean isNegative = false; if (s.charAt(0) == '-') { isNegative = true; s = s.substring(1); length--; } int extraBytes = length - bytes + 1; if (extraBytes < 0) { // Pad extra byte positions with zero for (int i = 0; i < -extraBytes; i++) { b[i] = 0x00; } } else if (extraBytes > 0) { // Truncate the high order digits of the number to fit s = s.substring(extraBytes); length -= extraBytes; extraBytes = 0; } // Translate the string digits into bytes for (int i = 0; i < length; i++) { String digit = s.substring(i, i + 1); b[i - extraBytes] = Byte.valueOf(digit); } // Add the sign byte if (isNegative) { b[bytes - 1] = minusSign; } else { b[bytes - 1] = noSign; } return b; } public static void main(String[] args) { long number = -456L; byte[] b = PackedDecimal.format(number, 5); System.out.println("Number: " + number + ", packed: " + byteToString(b)); number = 0L; b = PackedDecimal.format(number, 5); System.out.println("Number: " + number + ", packed: " + byteToString(b)); number = 5823L; b = PackedDecimal.format(number, 5); System.out.println("Number: " + number + ", packed: " + byteToString(b)); number = 123456L; b = PackedDecimal.format(number, 5); System.out.println("Number: " + number + ", packed: " + byteToString(b)); } public static String byteToString(byte[] b) { StringBuilder sb = new StringBuilder(); for (int i = 0; i < b.length; i++) { sb.append("0x"); sb.append(Integer.toHexString((int) b[i]).toUpperCase()); sb.append(" "); } return sb.toString(); }}这是测试结果。
Number: -456, packed: 0x0 0x4 0x5 0x6 0xD Number: 0, packed: 0x0 0x0 0x0 0x0 0xF Number: 5823, packed: 0x5 0x8 0x2 0x3 0xF Number: 123456, packed: 0x3 0x4 0x5 0x6 0xF
