Java实现把整数转换为英语单词的方法，实用代码

public class Solution {
HashMap<Integer, String> map = new HashMap<Integer, String>();
public String numberToWords(int num) {
fillMap();
StringBuilder sb = new StringBuilder();
if(num==0){
return map.get(0);
}
if(num >= 1000000000){
int extra = num/1000000000;
sb.append(convert(extra) + " Billion");
num = num%1000000000;
}
if(num >= 1000000){
int extra = num/1000000;
sb.append(convert(extra) + " Million");
num = num%1000000;
}
if(num >= 1000){
int extra = num/1000;
sb.append(convert(extra) + " Thousand");
num = num%1000;
}
if(num > 0){
sb.append(convert(num));
}
return sb.toString().trim();
}
public String convert(int num){
StringBuilder sb = new StringBuilder();
if(num>=100){
int numHundred = num/100;
sb.append(" " +map.get(numHundred)+ " Hundred");
num=num%100;
}
if(num > 0){
if(num>0 && num<=20){
sb.append(" "+map.get(num));
}else{
int numTen = num/10;
sb.append(" "+map.get(numTen*10));
int numOne=num%10;
if(numOne>0){
sb.append(" " + map.get(numOne));
}
}
}
return sb.toString();
}
public void fillMap(){
map.put(0, "Zero");
map.put(1, "One");
map.put(2, "Two");
map.put(3, "Three");
map.put(4, "Four");
map.put(5, "Five");
map.put(6, "Six");
map.put(7, "Seven");
map.put(8, "Eight");
map.put(9, "Nine");
map.put(10, "Ten");
map.put(11, "Eleven");
map.put(12, "Twelve");
map.put(13, "Thirteen");
map.put(14, "Fourteen");
map.put(15, "Fifteen");
map.put(16, "Sixteen");
map.put(17, "Seventeen");
map.put(18, "Eighteen");
map.put(19, "Nineteen");
map.put(20, "Twenty");
map.put(30, "Thirty");
map.put(40, "Forty");
map.put(50, "Fifty");
map.put(60, "Sixty");
map.put(70, "Seventy");
map.put(80, "Eighty");
map.put(90, "Ninety");
}
}