编程小技巧:阿拉伯数字转中文汉字的Java方法

之前做财务相关的系统时，阿拉伯数字需要转换成中文汉字。

当时知识储备不足。一直没有满意的方案。

今天特意思考这个问题，写下此方法，到目前为止算是最满意的方案了。

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

public class TestNumberToChinese {

    @Test
    public void testConvertNumberToChinese() {
        Assertions.assertArrayEquals(new Object[] { "零元"//
                , "零元" } //
                , new Object[] { TestNumberToChinese.convertNumberToChinese("0")//
                        , TestNumberToChinese.convertNumberToChinese("0.00") });
    }

    public static String convertNumberToChinese(String inputData) {

        Map<Integer, String> decimalUnit = new HashMap<>();
        decimalUnit.put(-2, "分");
        decimalUnit.put(-1, "角");
        decimalUnit.put(1, "元");
        decimalUnit.put(2, "拾");
        decimalUnit.put(3, "佰");
        decimalUnit.put(4, "仟");
        decimalUnit.put(5, "万");
        decimalUnit.put(6, "拾");// 十万
        decimalUnit.put(7, "佰");// 佰万
        decimalUnit.put(8, "仟");// 仟万
        decimalUnit.put(9, "亿");
        decimalUnit.put(10, "拾");// 十亿
        decimalUnit.put(11, "佰");// 佰亿
        decimalUnit.put(12, "仟");// 仟亿
        decimalUnit.put(13, "兆");
        decimalUnit.put(14, "拾");// 十兆
        decimalUnit.put(15, "佰");// 佰兆
        decimalUnit.put(16, "仟");// 仟兆

        List<String> extraUnit = new ArrayList<>();
        extraUnit.add("万");
        extraUnit.add("亿");
        extraUnit.add("兆");

        Map<Integer, String> unitCount = new HashMap<>();
        unitCount.put(0, "零");
        unitCount.put(1, "壹");
        unitCount.put(2, "贰");
        unitCount.put(3, "叁");
        unitCount.put(4, "肆");
        unitCount.put(5, "伍");
        unitCount.put(6, "陆");
        unitCount.put(7, "柒");
        unitCount.put(8, "捌");
        unitCount.put(9, "玖");

        StringBuffer outputBufferData = new StringBuffer();

        String integerData = null;
        String scaleData = null;

        Pattern decimalPattern = Pattern.compile("^(\\d{1,16})\\.(\\d{0,2})#34;);
        Matcher decimalMatcher = decimalPattern.matcher(inputData);
        Pattern integerPattern = Pattern.compile("^(\\d{1,16})#34;);
        Matcher integerMatcher = integerPattern.matcher(inputData);
        if (decimalMatcher.find()) {// 小数的场合
            integerData = decimalMatcher.group(1);
            scaleData = decimalMatcher.group(2);
        } else if (integerMatcher.matches()) {// 整数的场合
            integerData = inputData;
        }

        // 转换整数
        if (integerData != null && integerData != "") {
            for (int k = 0; k < integerData.length(); k++) {
                char inputChar = integerData.charAt(k);
                int currentUnitCount = Character.getNumericValue(inputChar);
                String currentUnit = decimalUnit.get(integerData.length() - k);
                String numToChinese = null;
                if (currentUnitCount == 0) {
                    numToChinese = unitCount.get(currentUnitCount);
                    if (k == integerData.length() - 1) {
                        numToChinese = unitCount.get(currentUnitCount) + currentUnit;
                    } else if (extraUnit.contains(currentUnit)) {
                        numToChinese = currentUnit;
                    }

                } else {
                    numToChinese = unitCount.get(currentUnitCount) + currentUnit;
                }
                outputBufferData.append(numToChinese);
            }
        }
        // 转换小数
        if (scaleData != null && scaleData != "") {
            for (int k = 0; k < scaleData.length(); k++) {
                char inputChar = scaleData.charAt(k);
                int currentUnitCount = Character.getNumericValue(inputChar);
                String currentUnit = decimalUnit.get(Math.negateExact(k + 1));
                String numToChinese = null;
                if (currentUnitCount == 0) {
                    numToChinese = unitCount.get(currentUnitCount);
                } else {
                    numToChinese = unitCount.get(currentUnitCount) + currentUnit;
                }
                outputBufferData.append(numToChinese);
            }
        }

        String ouputData = outputBufferData.toString();

        // 去除重复的零
        ouputData = ouputData.replaceAll("(零{2,})", "");
        if (!ouputData.equals("零元")) {
            // 去除末位的零
            ouputData = ouputData.replaceAll("(零)", "");
            // 去除不合理的单位
            ouputData = ouputData.replaceAll("^(零元)", "");
            ouputData = ouputData.replaceAll("(亿万)", "亿");
            ouputData = ouputData.replaceAll("(兆亿)", "兆");
            ouputData = ouputData.replaceAll("^(兆)", "");
            ouputData = ouputData.replaceAll("^(亿)", "");
            ouputData = ouputData.replaceAll("^(万)", "");
        }

        return ouputData;
    }
}