java实现人民币大写转换

简介

将阿拉伯数字转换成中文大写，如将123.45转换成壹佰贰拾叁元肆角伍分。

代码实现

import java.util.regex.Pattern;

public class CurrencyUtil {

  private CurrencyUtil() {
  }

  //无效字符
  private static final Pattern INVALID_CHARACTER = Pattern.compile("[^,.\\d]");
  //有效数字格式
  private static final Pattern VALID_DIGIT = Pattern
      .compile("^((\\d{1,3}(,\\d{3})*(.((\\d{3},)*\\d{1,3}))?)|(\\d+(.\\d+)?))$");
  //最大值999亿多
  private static final double MAXIMUM_NUMBER = 99999999999.99;
  //货币符号
  private static final String CN_ZERO = "零";
  private static final String CN_ONE = "壹";
  private static final String CN_TWO = "贰";
  private static final String CN_THREE = "叁";
  private static final String CN_FOUR = "肆";
  private static final String CN_FIVE = "伍";
  private static final String CN_SIX = "陆";
  private static final String CN_SEVEN = "柒";
  private static final String CN_EIGHT = "捌";
  private static final String CN_NINE = "玖";
  private static final String CN_TEN = "拾";
  private static final String CN_HUNDRED = "佰";
  private static final String CN_THOUSAND = "仟";
  private static final String CN_TEN_THOUSAND = "万";
  private static final String CN_HUNDRED_MILLION = "亿";
  private static final String CN_DOLLAR = "元";
  private static final String CN_TEN_CENT = "角";
  private static final String CN_CENT = "分";
  private static final String CN_INTEGER = "整";
  //整数 0-9
  private static final String[] DIGITS = {
      CN_ZERO, CN_ONE, CN_TWO, CN_THREE, CN_FOUR, CN_FIVE, CN_SIX, CN_SEVEN, CN_EIGHT, CN_NINE};
  //基数 百 千
  private static final String[] RADICES = {"", CN_TEN, CN_HUNDRED, CN_THOUSAND};
  //大基数 万 亿
  private static final String[] BIGRADICES = {"", CN_TEN_THOUSAND, CN_HUNDRED_MILLION};
  //小数 角 分
  private static final String[] DECIMALS = {CN_TEN_CENT, CN_CENT};

  private static String convertCurrency(String currencyDigits) {
    if (currencyDigits == null || currencyDigits.length() == 0) {
      System.out.println("不能为空");
      return "";
    }
    //字符串中不能包含除了逗号点号和数字的其他字符
    if (INVALID_CHARACTER.matcher(currencyDigits).matches()) {
      System.out.println("包含无效字符");
      return "";
    }
    if (!VALID_DIGIT.matcher(currencyDigits).matches()) {
      System.out.println("数字格式错误");
      return "";
    }
    //移除所有的逗号
    currencyDigits = currencyDigits.replaceAll(",", "");
    //移除所有的前导零
    currencyDigits = currencyDigits.replaceAll("^0+", "");
    // Assert the number is not greater than the maximum number.
    if (Double.parseDouble(currencyDigits) > MAXIMUM_NUMBER) {
      return "";
    }
    //根据点号分割成两部分整数和小数
    String[] parts = currencyDigits.split("\\.");
    //整数
    String integral;
    //小数
    String decimal;
    if (parts.length > 1) {
      integral = parts[0];
      decimal = parts[1];
      //小数最多保留2位
      if (decimal.length() >= 2) {
        decimal = decimal.substring(0, 2);
      } else {
        decimal = decimal.substring(0, 1);
      }
    } else {
      integral = parts[0];
      decimal = "";
    }
    StringBuilder outputCharacters = new StringBuilder();
    //处理整数
    if (Integer.parseInt(integral) > 0) {
      int zeroCount = 0;
      for (int i = 0; i < integral.length(); i++) {
        int p = integral.length() - i - 1;
        int d = integral.charAt(i) - '0';
        int quotient = p / 4;
        int modulus = p % 4;
        if (d == 0) {
          zeroCount++;
        } else {
          if (zeroCount > 0) {
            outputCharacters.append(DIGITS[0]);
          }
          zeroCount = 0;
          outputCharacters.append(DIGITS[d]).append(RADICES[modulus]);
        }
        if (modulus == 0 && zeroCount < 4) {
          outputCharacters.append(BIGRADICES[quotient]);
        }
      }
      outputCharacters.append(CN_DOLLAR);
    }
    //处理小数
    if (!decimal.isEmpty()) {
      for (int i = 0; i < decimal.length(); i++) {
        int d = decimal.charAt(i) - '0';
        int ds = decimal.charAt(decimal.length() - 1) - '0';
        if (d == 0) {
          if (ds != 0) {
            outputCharacters.append(DIGITS[d]);
          }
        } else {
          outputCharacters.append(DIGITS[d]).append(DECIMALS[i]);
        }
      }
    }
    if (outputCharacters.length() == 0) {
      outputCharacters.append(CN_ZERO).append(CN_DOLLAR);
    }
    if (decimal.isEmpty()) {
      outputCharacters.append(CN_INTEGER);
    }
    return outputCharacters.toString();
  }

  public static void main(String[] args) {
    System.out.println(convertCurrency("12.045"));
  }
}

最大支持999亿，支持小数。

参考

人民币大写在线转换工具 - 917118