java 时间戳 、时间差计算（秒、分钟、小时、天数、月份、年）

以下代码就是时间差计算（秒、分钟、小时、天数、月份、年）

package me.zhengjie;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.junit.Test;

public class DemoTest {
	@Test
	public void run1() {
		System.out.println("run1()");
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
		String startDateStr = "2012-01-20 00:00:00.000";
		String endDateStr = "2019-11-01 00:00:00.000";
		try {
			Date startDate = sdf.parse(startDateStr);
			Date endDate = sdf.parse(endDateStr);
			String timeDifference = this.convert(startDate, endDate);
			System.out.println(timeDifference);
		} catch (ParseException e) {
			e.printStackTrace();
			System.out.println("日期格式化失败");
		}
	}

	public String convert(Date startDate,Date endDate) {
		long startTime = startDate.getTime();//获取毫秒数
		long endTime = endDate.getTime();	 //获取毫秒数
		long timeDifference = endTime-startTime;
		long second = timeDifference/1000;	//计算秒

		if(second<60) {
			return second+"秒前";
		}else {
			long minute = second/60;
			if(minute<60) {
				return minute+"分钟前";
			}else {
				long hour = minute/60;
				if(hour<24) {
					return hour+"时前";
				}else {
					long day = hour/24;
					if(day<30) {
						return day+"天前";
					}else {
						long month = day/30;
						if(month<12) {
							return day+"月前";
						}else {
							long year = month/12;
							return year+"年前";
						}
					}

				}
			}
		}
	}

}