java计算工龄

计算工龄原则：若是2000-10-12作为开始工作时间，则到下一年的2001-10-13算为一年。有个bug，不满一年的工龄是错误的。

import java.util.Date;
import java.util.Calendar;

public int workAge(Date nowTime, Date workTime){
    int year = 0;
    //当前时间的年月日
    Calendar cal = Calendar.getInstance();
    cal.setTime(nowTime);
    int nowYear = cal.get(Calendar.YEAR);
    int nowMonth = cal.get(Calendar.MONTH);
    int nowDay = cal.get(Calendar.DAY_OF_MONTH);

    //开始工作时间的年月日
    cal.setTime(workTime);
    int workYear = cal.get(Calendar.YEAR);
    int workMonth = cal.get(Calendar.MONTH);
    int workDay = cal.get(Calendar.DAY_OF_MONTH);

    //得到工龄
    year = nowYear - workYear; //得到年差
    //若目前月数少于开始工作时间的月数，年差-1
    if (nowMonth < workMonth){
        year  = year - 1;
    }else if (nowMonth == workMonth){
        //当月数相等时，判断日数，若当月的日数小于开始工作时间的日数，年差-1
        if (nowDay < workDay){
            year = year - 1;
        }
    }

    return year;
}

　　　　　 /**
	 * 计算工龄
	 * @param begin "yyyy-MM-dd"
	 * @return double
	 * @throws ParseException
	 */	 
	 public static double workYears(String begin) {

	        Calendar dayEnd = Calendar.getInstance();
	        Calendar dayBegin = Calendar.getInstance();

	            try {
					dayBegin.setTime(new SimpleDateFormat("yyyy-MM-dd").parse(begin));
				} catch (ParseException e) {
					e.printStackTrace();
				}

	        //初始计算
	        double result= dayEnd.get(Calendar.MONTH) +dayEnd.get(Calendar.YEAR)*12
	                -dayBegin.get(Calendar.MONTH) - dayBegin.get(Calendar.YEAR)*12;

	        //BigDecimal.ROUND_HALF_UP表示四舍五入，BigDecimal.ROUND_HALF_DOWN也是五舍六入，BigDecimal.ROUND_UP表示进位处理（就是直接加1），BigDecimal.ROUND_DOWN表示直接去掉尾数。
	        return new BigDecimal(result/12).setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
	    }