[Java] 计算两个日期之间的差(年月日)

怼烎@ 2022-06-18 01:36 325阅读 0赞

在项目中有这样的需求： 需要显示剩余的年月日。如下表：

> 起始时间 截至期 有效期

2011-01-01 2013-12-31 3年

> 2011-01-01 2011-01-01 1天

代码如下： 主要是参考 remainDateToString（）方法

/**
     * 处理平台的时间转换
     * @author alf
     * 2011-8-31 上午09:21:39
     */
    public class DateHandler {
    	private static Calendar calS=Calendar.getInstance();
    	private static Pattern   p   =   Pattern.compile("\\d{4}-\\d{2}-\\d{2}");//定义整则表达式
    	private DateHandler(){}
    	/**
    	 * 计算剩余时间
    	 * @param startDateStr
    	 * @param endDateStr
    	 * @return
    	 */
    	public static String remainDateToString(String startDateStr, String endDateStr){
    		java.util.Date startDate = null;
    		java.util.Date endDate= null;
    		try {
    			startDate = new SimpleDateFormat("yyyy-MM-dd").parse(startDateStr);
    		} catch (ParseException e) {
    			e.printStackTrace();
    			return "";
    		}
    		try {
    			endDate = new SimpleDateFormat("yyyy-MM-dd").parse(endDateStr);
    		} catch (ParseException e) {
    			e.printStackTrace();
    			return "";
    		}
    		calS.setTime(startDate);
    		int startY = calS.get(Calendar.YEAR);
    		int startM = calS.get(Calendar.MONTH);
    		int startD = calS.get(Calendar.DATE);
    		int startDayOfMonth = calS.getActualMaximum(Calendar.DAY_OF_MONTH);
    		
    		calS.setTime(endDate);
    		int endY = calS.get(Calendar.YEAR);
    		int endM = calS.get(Calendar.MONTH);
    		//处理2011-01-10到2011-01-10，认为服务为一天
    		int endD = calS.get(Calendar.DATE)+1;
    		int endDayOfMonth = calS.getActualMaximum(Calendar.DAY_OF_MONTH);
    		
    		StringBuilder sBuilder = new StringBuilder();
    		if (endDate.compareTo(startDate)<0) {
    			return sBuilder.append("过期").toString();
    		}
    		int lday = endD-startD;
    		if (lday<0) {
    			endM = endM -1;
    			lday = startDayOfMonth+ lday;
    		}
    		//处理天数问题，如：2011-01-01 到	2013-12-31 	2年11个月31天     实际上就是3年
    		if (lday == endDayOfMonth) {
    			endM = endM+1;
    			lday =0;
    		}
    		int mos = (endY - startY)*12 + (endM- startM);
    		int lyear = mos/12;
    		int lmonth = mos%12;
    		if (lyear >0) {
    			sBuilder.append(lyear+"年");
    		}
    		if (lmonth > 0) {
    			sBuilder.append(lmonth+"个月");
    		}
    		if (lday >0 ) {
    			sBuilder.append(lday+"天");
    		}
    		return sBuilder.toString();
    	}
    	
    	/*
    	 * 转换 dataAndTime 2013-12-31 23:59:59 到
    	 * date 2013-12-31
    	 */
    	public static String getDate(String dateAndTime){
    		if (dateAndTime != null && !"".equals(dateAndTime.trim())) {
    			Matcher   m   =  p.matcher(dateAndTime); 
    			if (m.find()) {
    				  return dateAndTime.subSequence(m.start(), m.end()).toString();
    			}
    		}
    		return "data error";
    	}
    	
    	public static void main(String[] args) {
    		System.out.println(remainDateToString("2004-02-29", "2005-04-01"));
    		System.out.println("A");
    		Date time1=new Date();
    	 	SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
    	 	String tm=sdf.format(time1);//tm就是昨天的日期的字符串表示
    	 	System.out.println(tm);
    	}
    }