Java 将数字金额转成中文大写

一个 Java 将数字金额转成中文大写的工具类，还不是很完善。

import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class ChineseYuanUtil {
 
    private static final Pattern AMOUNT_PATTERN = Pattern.compile("^(0|[1-9]\\d{0,11})\\.(\\d\\d)$"); // 不考虑分隔符的正确性
    private static final char[] RMB_NUMS = "零壹贰叁肆伍陆柒捌玖".toCharArray();
    private static final String[] UNITS = { "元", "角", "分", "整" };
    private static final String[] U1 = { "", "拾", "佰", "仟" };
    private static final String[] U2 = { "", "万", "亿" };
 
    /**
     * 将金额（整数部分等于或少于 12 位，小数部分 2 位）转换为中文大写形式.
     * 
     * @param amount 金额数字
     * @return 中文大写
     * @throws IllegalArgumentException
     */
    public static String convert(String amount) throws IllegalArgumentException {
        // 去掉分隔符
        amount = amount.replace(",", "");
 
        // 验证金额正确性
        if (amount.equals("0.00")) {
            throw new IllegalArgumentException("金额不能为零.");
        }
        Matcher matcher = AMOUNT_PATTERN.matcher(amount);
        if (!matcher.find()) {
            throw new IllegalArgumentException("输入金额有误.");
        }
 
        String integer = matcher.group(1); // 整数部分
        String fraction = matcher.group(2); // 小数部分
 
        String result = "";
        if (!integer.equals("0")) {
            result += integer2rmb(integer) + UNITS[0]; // 整数部分
        }
        if (fraction.equals("00")) {
            result += UNITS[3]; // 添加[整]
        } else if (fraction.startsWith("0") && integer.equals("0")) {
            result += fraction2rmb(fraction).substring(1); // 去掉分前面的[零]
        } else {
            result += fraction2rmb(fraction); // 小数部分
        }
 
        return result;
    }
 
    // 将金额小数部分转换为中文大写
    private static String fraction2rmb(String fraction) {
        char jiao = fraction.charAt(0); // 角
        char fen = fraction.charAt(1); // 分
        return (RMB_NUMS[jiao - '0'] + (jiao > '0' ? UNITS[1] : ""))
                + (fen > '0' ? RMB_NUMS[fen - '0'] + UNITS[2] : "");
    }
 
    // 将金额整数部分转换为中文大写
    private static String integer2rmb(String integer) {
        StringBuilder buffer = new StringBuilder();
        // 从个位数开始转换
        int i, j;
        for (i = integer.length() - 1, j = 0; i >= 0; i--, j++) {
            char n = integer.charAt(i);
            if (n == '0') {
                // 当 n 是 0 且 n 的右边一位不是 0 时，插入[零]
                if (i < integer.length() - 1 && integer.charAt(i + 1) != '0') {
                    buffer.append(RMB_NUMS[0]);
                }
                // 插入[万]或者[亿]
                if (j % 4 == 0) {
                    if (i > 0 && integer.charAt(i - 1) != '0' || i > 1 && integer.charAt(i - 2) != '0'
                            || i > 2 && integer.charAt(i - 3) != '0') {
                        buffer.append(U2[j / 4]);
                    }
                }
            } else {
                if (j % 4 == 0) {
                    buffer.append(U2[j / 4]); // 插入[万]或者[亿]
                }
                buffer.append(U1[j % 4]); // 插入[拾]、[佰]或[仟]
                buffer.append(RMB_NUMS[n - '0']); // 插入数字
            }
        }
        return buffer.reverse().toString();
    }
}

测试类：

public static void main(String[] args) {
       
       System.out.println(ChineseYuanUtil.convert("16,409.02"));
       System.out.println(ChineseYuanUtil.convert("1,409.50"));
       System.out.println(ChineseYuanUtil.convert("6,007.14"));
       System.out.println(ChineseYuanUtil.convert("1,680.32"));
       System.out.println(ChineseYuanUtil.convert("325.04"));
       System.out.println(ChineseYuanUtil.convert("4,321.00"));
       System.out.println(ChineseYuanUtil.convert("0.05"));
 
       System.out.println(ChineseYuanUtil.convert("1234,5678,9012.34"));
       System.out.println(ChineseYuanUtil.convert("1000,1000,1000.10"));
       System.out.println(ChineseYuanUtil.convert("9005,9009,9009.99"));
       System.out.println(ChineseYuanUtil.convert("5432,0001,0001.01"));
       System.out.println(ChineseYuanUtil.convert("1000,0000,1110.00"));
       System.out.println(ChineseYuanUtil.convert("1010,0000,0001.11"));
       System.out.println(ChineseYuanUtil.convert("1012,0000,0000.01"));
   }

输出结果：

壹万陆仟肆佰零玖元零贰分
壹仟肆佰零玖元伍角
陆仟零柒元壹角肆分
壹仟陆佰捌拾元叁角贰分
叁佰贰拾伍元零肆分
肆仟叁佰贰拾壹元整
伍分
壹仟贰佰叁拾肆亿伍仟陆佰柒拾捌万玖仟零壹拾贰元叁角肆分
壹仟亿零壹仟万零壹仟元壹角
玖仟零伍亿玖仟零玖万玖仟零玖元玖角玖分
伍仟肆佰叁拾贰亿零壹万零壹元零壹分
壹仟亿零壹仟壹佰壹拾元整
壹仟零壹拾亿零壹元壹角壹分
壹仟零壹拾贰亿元零壹分