我工作中所使用过的时间工具类
package test;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class TimeUtil {
public static void main(String[] args) throws ParseException{
SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd");
Date bb = sf.parse("2015-10-31");
Date ee = sf.parse("2015-10-31");
SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
Date d = sdf.parse("4/1/2020 0:0:0");
System.out.println(d);
System.out.println(bb.before(ee));
System.out.println(bb.getTime() - ee.getTime());
Date now = sf.parse(sf.format(new Date())); //系统时间（现在）
System.out.println("系统时间是" + now);
//获得两个日期相差多少个月
System.out.println("获得两个日期相差多少个月: " + getDiffMonth(bb , ee));
//获得两个日期相差多少天
System.out.println("获得两个日期相差多少天: " + getDiffDays(bb , ee));
//获得该日期中该月最大天数
System.out.println("获得该日期中该月最大天数: " + getDaysOfMonth(ee));
//获得本月第一天
System.out.println("获得本月第一天" + getFirstDayOfMonth(bb));
//获得本月最后一天
System.out.println("获得本月最后一天" + getLastDayOfMonth(bb));
//获得本月最后一天
getFirstAndLastDay(bb);
//获得日期
getDays(ee);
//new一个date类型数据，返回的是String
System.out.println(getCurrentTime());
}
//两个日期相差多少月份
public static int getDiffMonth(Date beginDate,Date endDate){
Calendar calbegin = Calendar.getInstance();
Calendar calend = Calendar.getInstance();
calbegin.setTime(beginDate);
calend.setTime(endDate);
int m_begin = calbegin.get(Calendar.MARCH) + 1; //获得开始月份日期
int m_end = calend.get(Calendar.MONTH) + 1;
int checkMonth = m_end - m_begin
+ (calend.get(Calendar.YEAR) - calbegin.get(Calendar.YEAR))
* 12;
return checkMonth ;
}
//两个日期相差多少天
public static int getDiffDays(Date begin , Date end){
Long times = end.getTime() - begin.getTime();
int days = (int) (times/1000/60/60/24);
return days;
}
//获得本月有多少天
public static int getDaysOfMonth(Date begin){
Calendar cal = Calendar.getInstance();
cal.setTime(begin);
int days = cal.getActualMaximum(Calendar.DATE);
//int day = cal.get(Calendar.DAY_OF_YEAR); //获得今天是本年的第几天
return days;
}
//获得本月第一天
public static Date getFirstDayOfMonth(Date date){
Calendar cal = Calendar.getInstance();
cal.setTime(date);
cal.set(Calendar.MONTH, cal.get(Calendar.MONTH));
cal.set(Calendar.DAY_OF_MONTH, 1);
return cal.getTime();
}
//获得本月最后一天
public static Date getLastDayOfMonth(Date date) {
Calendar cal = Calendar.getInstance();
cal.setTime(date);
cal.set(Calendar.MONTH, cal.get(Calendar.MONTH) + 1);
cal.set(Calendar.DAY_OF_MONTH, 0);
return cal.getTime();
}
//获得本月第一天与本月最后一天
public static void getFirstAndLastDay(Date date){
Calendar c = Calendar.getInstance();
c.setTime(date);
c.set(Calendar.MONTH, c.get(Calendar.MONTH)); //0是本月
c.set(Calendar.DAY_OF_MONTH, 1);
System.out.println("本月的第一天: " + c.getTime());
c.set(Calendar.MONTH, c.get(Calendar.MONTH)+1);
c.set(Calendar.DAY_OF_MONTH, 0);
System.out.println("本月的最后一天: " + c.getTime());
}
//开始日期和结束日期n天后的日期
public static void getDays(Date date){
Calendar cal = Calendar.getInstance();
cal.setTime(date);
//开始时间是两天后的日期
cal.add(Calendar.DAY_OF_MONTH, 2);
Date begin = cal.getTime();
//结束日期是开始日期+2在加n天后的日期
cal.add(Calendar.DAY_OF_MONTH, 11);
Date end = cal.getTime();
System.out.println(begin);
System.out.println(end);
}
//new一个date类型的时间
public static String getCurrentTime(){
Calendar cal = Calendar.getInstance();
//cal.add(Calendar.MONTH, -1);
SimpleDateFormat sf = new SimpleDateFormat("yyyyMM");
return sf.format(cal.getTime());
}
//获得当前月的第一天
public static Date getFirstDayOfNow(){
Calendar calendar = Calendar.getInstance();// 获取当前日期
calendar.add(Calendar.MONTH, 0);
calendar.set(Calendar.DAY_OF_MONTH, 1);// 设置为1号,当前日期既为本月第一天
calendar.set(Calendar.HOUR_OF_DAY, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.MILLISECOND, 0);
return calendar.getTime();
}
}
