30行，金額轉人民幣大寫的代碼

金額轉人民幣大寫是一種常見的要求，但是這一看似簡單的要求，實現起來卻並不容易。

前不久，我被問到了這樣一道題，當時寫了個算法，昨天晚上又和BJDP的人們討論了一下，覺得很有必要把這個算法寫下來。

總共37行，去掉空行還不到30行，就不多啰嗦解釋了。

 

public class ChineseCurrencyConverter {

    private static final String[] UNITS = {"億","仟","佰","拾","萬","仟","佰","拾","" };
    private static final String[] CHINESE_NUMBER = {"零","壹","貳","叄","肆","伍","陸","柒","捌","玖"};

    public static String convert(long yuan) {

        if (yuan >= 1e9 || yuan < 0) {
            return "這個數字超出解析范圍了";
        }
        String amount = String.valueOf(yuan);
        int len = amount.length();
        int unitsLen = UNITS.length;

        String chineseCurrency = "";
        for (int i = len - 1; i >= 0; i--) {
            chineseCurrency = number(amount.charAt(i)) + unit(amount.charAt(i), unitsLen - len + i) +chineseCurrency;
        }

        chineseCurrency = chineseCurrency.replaceAll("零+","零");
        chineseCurrency =  chineseCurrency + "元整";
        chineseCurrency = chineseCurrency.replaceAll("零萬","萬");
        chineseCurrency = chineseCurrency.replaceAll("零元","元");
        return chineseCurrency;
    }

    private static String number(char number) {
        return CHINESE_NUMBER[Integer.parseInt(String.valueOf(number))];
    }

    private static String unit(char number, int pos) {
        if(number == '0' && pos != UNITS.length - 5) {
            return "";
        }
        return UNITS[pos];
    }
}

 

 

下面是一些用來測試的代碼：

public class TestConverter  {

    public static void main(String[] args) {
        System.out.println(ChineseCurrencyConverter.convert(100));
        System.out.println(ChineseCurrencyConverter.convert(130));
        System.out.println(ChineseCurrencyConverter.convert(102));
        System.out.println(ChineseCurrencyConverter.convert(124));
        System.out.println(ChineseCurrencyConverter.convert(1000));
        System.out.println(ChineseCurrencyConverter.convert(10000));
        System.out.println(ChineseCurrencyConverter.convert(100000));
        System.out.println(ChineseCurrencyConverter.convert(1000000));
        System.out.println(ChineseCurrencyConverter.convert(10000000));
        System.out.println(ChineseCurrencyConverter.convert(10000000));
        System.out.println(ChineseCurrencyConverter.convert(100000000));
        System.out.println(ChineseCurrencyConverter.convert(1000000000));
        System.out.println(ChineseCurrencyConverter.convert(1002));
        System.out.println(ChineseCurrencyConverter.convert(1020));
        System.out.println(ChineseCurrencyConverter.convert(1200));
        System.out.println(ChineseCurrencyConverter.convert(10003));
        System.out.println(ChineseCurrencyConverter.convert(10030));
        System.out.println(ChineseCurrencyConverter.convert(10033));
        System.out.println(ChineseCurrencyConverter.convert(10330));
        System.out.println(ChineseCurrencyConverter.convert(13030));
        System.out.println(ChineseCurrencyConverter.convert(100030));
        System.out.println(ChineseCurrencyConverter.convert(100003));
        System.out.println(ChineseCurrencyConverter.convert(100300));
        System.out.println(ChineseCurrencyConverter.convert(103000));
        System.out.println(ChineseCurrencyConverter.convert(100303));
        System.out.println(ChineseCurrencyConverter.convert(1000004));
        System.out.println(ChineseCurrencyConverter.convert(10000005));
        System.out.println(ChineseCurrencyConverter.convert(10000006));
        System.out.println(ChineseCurrencyConverter.convert(12000006));
        System.out.println(ChineseCurrencyConverter.convert(10030006));
        System.out.println(ChineseCurrencyConverter.convert(10200006));
        System.out.println(ChineseCurrencyConverter.convert(100000007));
        System.out.println(ChineseCurrencyConverter.convert(1000000008));

    }
}

 

這些數字測試的結果還都正確。

這里沒有處理角和分，留給有想法的同學去嘗試一下吧。