java怎么获取一天的开始时间和结束时间

public static void main(String[] args) {
Calendar c1 = new GregorianCalendar();
c1.set(Calendar.HOUR_OF_DAY, 0);
c1.set(Calendar.MINUTE, 0);
c1.set(Calendar.SECOND, 0);
System.out.println(c1.getTime().toLocaleString());
Calendar c2 = new GregorianCalendar();
c2.set(Calendar.HOUR_OF_DAY, 23);
c2.set(Calendar.MINUTE, 59);
c2.set(Calendar.SECOND, 59);
System.out.println(c2.getTime().toLocaleString());
}

/**
* @param args
*/
public static void main(String[] args) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(new Date());
calendar.set(Calendar.HOUR_OF_DAY, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);

Date start = calendar.getTime();

calendar.add(Calendar.DAY_OF_MONTH, 1);
calendar.add(Calendar.SECOND, -1);

Date end = calendar.getTime();

System.out.println(start);
System.out.println(end);
}

/**
* @param args
* @throws ParseException
*/
public static void main(String[] args) throws ParseException {
Calendar calendar = Calendar.getInstance();
calendar.setTime(new Date());
calendar.set(Calendar.HOUR_OF_DAY, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);

Date start = calendar.getTime();

calendar.add(Calendar.DAY_OF_MONTH, 1);
calendar.add(Calendar.SECOND, -1);

Date end = calendar.getTime();

System.out.println(start);
System.out.println(end);

/* other way */
SimpleDateFormat formater = new SimpleDateFormat("yyyy/MM/dd");
SimpleDateFormat formater2 = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");

start = formater2.parse(formater.format(new Date())+ " 00:00:00");
end = formater2.parse(formater.format(new Date())+ " 23:59:59");

System.out.println(start);
System.out.println(end);
}