calender获取日期前几月_获取当前日期的前四个季度，其后在获取这四个季度的开始时间和结束时间...

Java codeimport java.text.SimpleDateFormat;

import java.util.Calendar;

public class T2 {

public static void main(String[] args) {

Calendar c = Calendar.getInstance();

int m = c.get(Calendar.MONTH) + 1; //月份

int s = (int)Math.ceil( (m - 1) / 3) + 1; //季度

System.out.println(s);

int em = (s - 1) * 3; //上一个季度最后一个月

Calendar sc = Calendar.getInstance();

sc.setTimeInMillis(c.getTimeInMillis());

sc.set(Calendar.MONTH, em);

sc.set(Calendar.DAY_OF_MONTH, 1);

sc.set(Calendar.HOUR_OF_DAY, 0);

sc.set(Calendar.MINUTE, 0);

sc.set(Calendar.SECOND, 0);

sc.set(Calendar.MILLISECOND, 0);

sc.add(Calendar.MILLISECOND, -1);

out(sc);//结束时间

Calendar ec = Calendar.getInstance();

ec.setTimeInMillis(c.getTimeInMillis());

ec.set(Calendar.MONTH, em - 1); //month 基于0,一月的值是0

ec.set(Calendar.DAY_OF_MONTH, 1);

ec.set(Calendar.HOUR_OF_DAY, 0);

ec.set(Calendar.MINUTE, 0);

ec.set(Calendar.SECOND, 0);

ec.set(Calendar.MILLISECOND, 0);

ec.add(Calendar.MONTH, -11); //向前12个月，但是-11

out(ec);//开始时间

}

protected static void out(Calendar c){

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

String str = sdf.format(c.getTime());

System.out.println(str);

}

}