Java Utililty Methods Number Convert

List of utility methods to do Number Convert

  1. HOME
  2. Java
  3. N
  4. Number Convert

Description

The list of methods to do Number Convert are organized into topic(s).

Method

intnumToBytes(byte[] buffer, long value)
Place a string representation of a long in an array of bytes without incurring allocation 
return numToBytes(buffer, value, 10);
intnumToBytes(byte[] buffer, long value, int radix)
num To Bytes 
return 0;
voidnumToBytes(long value, byte[] b, int off, int len)

Writes a signed integer into a byte array. 

long shift = value;
for (int i = len - 1; i >= 0; i--) {
    long v = shift & 0xff;
    if ((v & 0x80) > 0) {
        v -= 0x100;
    b[off + i] = (byte) v;
    shift = shift >> 8;
...
IntegernumToInt(Number n)
Converts a Number object into an Integer. 
return (Integer) (n.intValue());
StringnumToIPv4(StringBuilder host)
num To I Pv 
int i = findFirstMatch(host, ":/?", 0);
if (i < 0) {
    i = host.length();
return numToIPv4(host, 0, i);
StringnumToLetter(String input)
num To Letter 
StringBuffer sb = new StringBuffer();
byte[] bytes = input.getBytes();
for (int i = 0; i < bytes.length; i++) {
    if (i % 2 == 0) {
        sb.append((char) (bytes[i] + 49));
    } else {
        sb.append((char) (bytes[i] + 17));
return sb.toString();
intnumToPowerOf(int num, int toPowerOf)
num To Power Of 
return toPowerOf > 0 ? num << toPowerOf : (toPowerOf < 0 ? num >> toPowerOf : (toPowerOf == 0 ? 1 : num));
StringnumToStringWithOrder(long count)
num To String With Order 
if (count < 1000) {
    return "" + count;
int exp = (int) (Math.log(count) / Math.log(1000));
return String.format("%.1f %c", count / Math.pow(1000, exp), "KMGTPE".charAt(exp - 1));
StringnumToWords(long num)
Gets a word from a number in between 1-999 
String[] ones = new String[] { "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
int[] onesLen = new int[] { 3, 3, 5, 4, 5, 3, 5, 5, 4 };
String[] teens = new String[] { "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen",
        "seventeen", "eighteen", "nineteen" };
int[] teensLen = new int[] { 6, 6, 8, 8, 7, 7, 9, 8, 8 };
String[] tens = new String[] { "ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty",
        "ninety" };
int[] tensLen = new int[] { 3, 5, 6, 5, 5, 5, 7, 6, 6 };
...
doubleparseAmountConversionRate(String convRate)
Parse currency amount conversion rate string

Suitble for parse fields 10 and 11 

if (convRate == null || convRate.length() != 8)
    throw new IllegalArgumentException("Invalid amount converion rate argument: '" + convRate + "'");
BigDecimal bd = new BigDecimal(convRate);
int pow = bd.movePointLeft(7).intValue();
bd = new BigDecimal(convRate.substring(1));
return bd.movePointLeft(pow).doubleValue();