根据指定类型计算两个日期相差的时间

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

public class TimeUtil {
    
    public static void main(String[] args){
        System.out.println(dateDiff(new Date(), new Date(), Calendar.MINUTE));
    }

    /**
     * 根据指定类型计算两个日期相差的时间
     * eg. dateDiff(birth, today, Calendar.MONTH) 孩子的月龄
     * @param sDate    开始时间
     * @param eDate    结束时间
     * @param diffType 日期类型
     * @return 根据 diffType计算的 eDate - sDate 时差
     */
    public static Long dateDiff(Date sDate, Date eDate, int diffType) {
        java.util.Calendar calst = java.util.Calendar.getInstance();   
        java.util.Calendar caled = java.util.Calendar.getInstance();  
         
        calst.setTime(sDate);   
        caled.setTime(eDate); 
         
        long diffMill = caled.getTime().getTime() - calst.getTime().getTime();
        long rtn = 0;
        switch (diffType) {
        case Calendar.MILLISECOND:
            rtn = diffMill;
            break;
        case Calendar.SECOND:
            rtn = diffMill / 1000;
            break;
        case Calendar.MINUTE:
            rtn = diffMill / 1000 / 60;
            break;
        case Calendar.HOUR:
            rtn = diffMill / 1000 / 3600;
            break;
        case Calendar.DATE:
            rtn = diffMill / 1000 / 60 / 60 / 24;
            break;
        case Calendar.MONTH:
            rtn = diffMill / 1000 / 60 / 60 / 24 / 12;
            break;
        case Calendar.YEAR:
            rtn = diffMill / 1000 / 60 / 60 / 24 / 365;
            break;
        }
        return rtn;
    }
    
    
}