java 时间处理经典案例

package day1;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Scanner;

/*
* 计算促销日期
* 输入一个生成日期，一个保质期天数
* 促销日为过期前2周的周三*/
public class test2 {
public static void main(String[] args) throws ParseException {
Scanner read=new Scanner(System.in);
System.out.println("请输入生产日期YYYY-MMM-DD");
String datastr=read.nextLine();
System.out.println("请输入保质期的天数");
int day=Integer.parseInt(read.nextLine());
//string -> date
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
Date date=sdf.parse(datastr);
// date->Calendar
Calendar calendar=Calendar.getInstance();
calendar.setTime(date);
calendar.add(Calendar.DAY_OF_YEAR, day);
calendar.add(Calendar.DAY_OF_YEAR, -14);
calendar.set(Calendar.DAY_OF_WEEK, 4);
//calendar->date
date=calendar.getTime();
datastr=sdf.format(date);
System.out.println("促销日为"+datastr);

}

}