Java解析带有时间单位的字符串

近期遇到这样一个场景，需要将输入的“20s”解析成200ms，或者“1min”解析成60000ms等，没找到合适的工具类，暂且自己写了一个记录下来。

import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.tuple.Pair;

import java.util.concurrent.TimeUnit;

/**
 * @author: sea
 * @date: 2022/10/18 18:35
 */
public class TimeUtil {
    public static long parseUnitTimeToMillSeconds(String timeWithUnit) {
        Pair<Long, TimeUnit> pair = parseAndSplitTimeWithUnit(timeWithUnit);
        return pair.getRight().toMillis(pair.getLeft());
    }

    /**
     * 将带有时间单位的字符串进行分割
     * 比如：200ms 分割成 200和ms
     * 支持的时间单位：ns纳秒，us微妙，ms毫秒，s秒，min分钟，h小时，d天
     * 默认是ms，比如200，会解析成200ms
     * @param timeWithUnit
     * @return
     */
    public static Pair<Long, TimeUnit> parseAndSplitTimeWithUnit(String timeWithUnit) {
        if (StringUtils.isBlank(timeWithUnit)) {
            return Pair.of(0L, TimeUnit.MILLISECONDS);
        }

        char[] chars = timeWithUnit.toCharArray();
        int length = chars.length;
        int position = length - 1;
        while (position >= 0 && Character.isLetter(chars[position])) {
            position--;
        }
        position = Math.min(position + 1, length);
        String timeStr = StringUtils.substring(timeWithUnit, 0, position);
        long time = Long.parseLong(StringUtils.trim(timeStr));
        String unitStr = StringUtils.substring(timeWithUnit, position, length);
        if (StringUtils.isBlank(unitStr)) {
            return Pair.of(time, TimeUnit.MILLISECONDS);
        }

        TimeUnit unit = convertTimeUnit(unitStr);
        if (unit == null) {
            throw new IllegalArgumentException("不支持该时间单位：" + unitStr);
        }
        return Pair.of(time, unit);
    }

    private static TimeUnit convertTimeUnit(String unitStr) {
        TimeUnit timeUnit = null;
        unitStr = StringUtils.lowerCase(unitStr);
        unitStr = StringUtils.trim(unitStr);
        switch (unitStr) {
            case "ns":
                timeUnit = TimeUnit.NANOSECONDS;
                break;
            case "us":
                timeUnit = TimeUnit.MICROSECONDS;
                break;
            case "ms":
                timeUnit = TimeUnit.MILLISECONDS;
                break;
            case "s":
                timeUnit = TimeUnit.SECONDS;
                break;
            case "min":
                timeUnit = TimeUnit.MINUTES;
                break;
            case "h":
                timeUnit = TimeUnit.HOURS;
                break;
            case "d":
                timeUnit = TimeUnit.DAYS;
                break;
        }
        System.out.println(timeUnit);
        return timeUnit;
    }
}