package com.date;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class DateTest {
/**
* 备注 ： 月份从 0 开始 到 11
* @author
* @date 2018年4月3日 下午4:14:00
* @param args
*/
public static void main(String[] args) {
System.out.println(getFirstDayOfMonth(2018, 1));
System.out.println(getLastDayOfMonth(2018, 1));
}
/**
* 得到本月的第一天
*
* @return
*/
public static String getMonthFirstDay() {
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
return dateFormat(“yyyy-MM-dd”, calendar.getTime());
}
/**
* 得到本月的最后一天
*
* @return
*/
public static String getMonthLastDay() {
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
return dateFormat(“yyyy-MM-dd”, calendar.getTime());
}
private static String dateFormat(String formate, Date time) {
SimpleDateFormat format = new SimpleDateFormat(formate);
return format.format(time);
}
/**
*
* @param year
* int 年份
* @param month
* int 月份
*
* @return int 某年某月的最后一天
*/
private static int getLastDayOfMonth(int year, int month) {
Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, month);
// 某年某月的最后一天
return cal.getActualMaximum(Calendar.DATE);
}
private static int getFirstDayOfMonth(int year, int month) {
Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, month);
// 某年某月的第一天
return cal.getActualMinimum(Calendar.DATE);
}
}
