常用类之日期

    package com.yuan.temp;
    
    import java.text.ParseException;
    import java.text.SimpleDateFormat;
    import java.util.Calendar;
    import java.util.Date;
    
    public class DateUtils {
        private static String format = "yyyy-MM-dd HH:mm:ss";
    
        private DateUtils() {
        }
    
        /**
        * 将字符串转化为指定格式的日期
        *
        * @param date   时间
        * @param format 格式
        * @return
        * @throws ParseException
        */
        public static Date stringToDate(String date, String format) throws ParseException {
            SimpleDateFormat sdf = new SimpleDateFormat(format);
            return sdf.parse(date);
        }
    
        public static Date stringToDate(String date) throws ParseException {
            return stringToDate(date, format);
        }
    
        /**
        * 将日期转化为指定格式的字符串
        *
        * @param date   时间
        * @param format 格式
        * @return
        */
        public static String dategToString(Date date, String format) {
            SimpleDateFormat sdf = new SimpleDateFormat(format);
            return sdf.format(date);
        }
    
        public static String dategToString(Date date) {
            return dategToString(date, format);
        }
    
        /**
        * 演示日历类获取日期
        */
        public static void calendarDemo1() {
            Calendar calendar = Calendar.getInstance();
    
            int yeay = calendar.get(Calendar.YEAR);
            int month = calendar.get(Calendar.MONTH) + 1;
            int day = calendar.get(Calendar.DATE);
    
            System.out.println("当前日期 = " + yeay + "年" + month + "月" + day + "日");
    
        }
        /**
        * 演示日历类获取日期
        */
        public static void calendarDemo2() {
            Calendar calendar = Calendar.getInstance();
    
            //去年的今天
            calendar.add(Calendar.YEAR, -1);
            int yeay = calendar.get(Calendar.YEAR);
            int month = calendar.get(Calendar.MONTH) + 1;
            int day = calendar.get(Calendar.DATE);
    
            System.out.println("当前日期 = " + yeay + "年" + month + "月" + day + "日");
    
        }
    
        /**
        * 演示日历类获取日期
        */
        public static void calendarDemo3() {
            Calendar calendar = Calendar.getInstance();
    
            //设置当前日历2008/8/8
            calendar.set(2008, 8 - 1, 8);
            int yeay = calendar.get(Calendar.YEAR);
            int month = calendar.get(Calendar.MONTH) + 1;
            int day = calendar.get(Calendar.DATE);
    
            System.out.println("当前日期 = " + yeay + "年" + month + "月" + day + "日");
    
        }
    }

【System.out.println(new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss").format(new Date(fb.lastModified())));】