package com.swift.oa;
import java.text.SimpleDateFormat;
import java.util.Calendar;
public class APP4 {
public static void main(String[] args) {
// TODO Auto-generated method stub
String firstDay = getFirstDay(2022,12,"yyyy-MM-dd");
String lastDay = getLastDay(2022,12,"yyyy-MM-dd");
System.out.println(firstDay);
System.out.println(lastDay);
}
/**
* 根据年月获取月初第一天日期
* @param year
* @param month
* @return
*/
public static String getFirstDay(int year,int month,String format) {
Calendar cale = Calendar.getInstance();
cale.set(Calendar.YEAR,year); //赋值年份
cale.set(Calendar.MONTH, month-1);//赋值月份
int lastDay = cale.getActualMinimum(Calendar.DAY_OF_MONTH);//获取月最大天数
cale.set(Calendar.DAY_OF_MONTH, lastDay);//设置日历中月份的最大天数
SimpleDateFormat sdf = new SimpleDateFormat(format);//格式化日期yyyy-MM-dd
String lastDayOfMonth = sdf.format(cale.getTime());
return lastDayOfMonth;
}
/**
* 根据年月获取月末最后一天日期
* @param year
* @param month
* @return
*/
public static String getLastDay(int year,int month,String format) {
Calendar cale = Calendar.getInstance();
cale.set(Calendar.YEAR,year);//赋值年份
cale.set(Calendar.MONTH, month-1);//赋值月份
int lastDay = cale.getActualMaximum(Calendar.DAY_OF_MONTH);//获取月最大天数
cale.set(Calendar.DAY_OF_MONTH, lastDay);//设置日历中月份的最大天数
SimpleDateFormat sdf = new SimpleDateFormat(format); //格式化日期yyyy-MM-dd
String lastDayOfMonth = sdf.format(cale.getTime());
return lastDayOfMonth;
}
}