Apakah kaedah untuk menulis kelas alat tarikh Java?

Kelas alat tarikh Java ditulis

Tukar rentetan kepada tarikh yang sepadan

Date date = simpleDateFormat.parse(string);

Tukar tarikh kepada rentetan

String string = simpleDateFormat.format(date);

Nota bahawa pengecualian akan dilemparkan kerana format yang mungkin ditakrifkan tidak sepadan dengan format yang disediakan oleh rentetan sebenar.

Tukar tarikh aksara Cina tahun, bulan dan hari kepada tarikh dengan - - pemisah

public static void main(String[] args) throws ParseException {
		//统一日期格式
		String StrVal = "2018年05月22日";
		Date d1 = new SimpleDateFormat("yyyy年MM月dd日").parse(StrVal);
		SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
		String time = format.format(d1);
		System.out.println(time);
	}

    /**
     * 将日期对象格式化为指定格式的日期字符串
     * @param date 传入的日期对象
     * @param format 格式
     * @return
     */
    public static String formatDate(Date date,String format){
        String result="";
        SimpleDateFormat sdf=new SimpleDateFormat(format);
        if(date!=null){
            result=sdf.format(date);
        }
        return result;
    }
    /**
     * 将日期字符串转换成一个日期对象 
     * @param dateStr 日期字符串
     * @param format 格式
     * @return
     * @throws ParseException 
     */
    public static Date formatDate(String dateStr,String format) throws ParseException{
        SimpleDateFormat sdf=new SimpleDateFormat(format);
        return sdf.parse(dateStr);
    }
    public static void main(String[] args) throws ParseException {
        Date date=new Date();
        System.out.println(formatDate(date,"yyyy-MM-dd"));
        System.out.println(formatDate(date,"yyyy-MM-dd HH:mm:ss"));
        System.out.println(formatDate(date,"yyyy年MM月dd日HH时mm分ss秒"));
        String dataStr="1989-11-02 18:01:41";
        Date date2=formatDate(dataStr,"yyyy-MM-dd HH:mm:ss");
        System.out.println(formatDate(date2,"yyyy-MM-dd HH:mm:ss"));
    }

Jalankan output:

2016-11 -02

2016-11-02 18:06:50

November 02, 2016 18:06:50

1989-11-02 18:02-1989 :41

Kelas SimpleDateFormat digunakan terutamanya untuk penukaran jenis tarikh, pemformatan tarikh yang biasa digunakan

    public static void main(String[] args) {
        //默认输出格式
        Date date=new Date();
        System.out.println(date);
        //日期格式化显示，首先定义格式
        SimpleDateFormat sdf1=new SimpleDateFormat("yyyyMMdd");
        SimpleDateFormat sdf2=new SimpleDateFormat("yyyy-MM-dd");
        SimpleDateFormat sdf3=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        SimpleDateFormat sdf4=new SimpleDateFormat("yyyy年MM月dd日HH时mm分ss秒");
        //将格式应用于日期
        System.out.println(sdf1.format(date));
        System.out.println(sdf2.format(date));
        System.out.println(sdf3.format(date));
        System.out.println(sdf4.format(date));
    }

Kendalian masa kelas kalendar JavaCalendar

Kalendar mempunyai DAY_OF_WEEK yang boleh mengembalikan hari dalam seminggu; >Kendalikan kalendar

import java.util.Calendar;
public class Test {
    public static void main(String[] args) {
        String[] weekDays = {"星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"};
        Calendar calendar=Calendar.getInstance();
        System.out.println("今天是"+weekDays[calendar.get(Calendar.DAY_OF_WEEK)-1]);
    }
}

Dapatkan masa

Biasa digunakan untuk menetapkan nilai tahun, bulan, hari, jam, nilai 6 minit dan saat, sila ambil perhatian bahawa subskrip bulan bermula dari 0, jadi untuk mendapatkan bulan, +1 Tetapkan pada tarikh tertentu, anda boleh menetapkan tahun, bulan, hari, jam, minit dan saat pada satu masa Sejak langganan bulan bermula dari 0, bulan perlu -1

    public static void main(String[] args) {
        //默认输出格式
    	Date now = new Date();
	SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
	String time = format.format(now);
	System.out.println(time);
    	Calendar calendar = Calendar.getInstance();
    	calendar.setTime(now);
    	calendar.add(Calendar.MONTH, 1);
    	SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    	String nowTime = sdf.format(calendar.getTime());
    	System.out.println(nowTime);
    	calendar.add(Calendar.MONTH, -2);
    	String nowTime2 = sdf.format(calendar.getTime());
    	System.out.println(nowTime2);
    }

Pengiraan masa

    public static void main(String[] args) {
        //默认输出格式
    	Date now = new Date();
    	SimpleDateFormat nowSdf = new SimpleDateFormat("yyyy-MM-dd");
        System.out.println(nowSdf.format(now));
        Calendar calendar = Calendar.getInstance();
        // 赋值时年月日时分秒常用的6个值，注意月份下标从0开始，所以取月份要+1
        System.out.println("年:" + calendar.get(Calendar.YEAR));
        System.out.println("月:" + (calendar.get(Calendar.MONTH) + 1));       
        System.out.println("日:" + calendar.get(Calendar.DAY_OF_MONTH));
        System.out.println("时:" + calendar.get(Calendar.HOUR_OF_DAY));
        System.out.println("分:" + calendar.get(Calendar.MINUTE));
        System.out.println("秒:" + calendar.get(Calendar.SECOND));
    	SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    	String nowTime2 = sdf.format(calendar.getTime());
    	System.out.println(nowTime2);
    }

Pengiraan tarikh

Dapatkan bilangan hari minimum dan maksimum dalam bulan ini

    public static void main(String[] args) {
        //默认输出格式
    	Date now = new Date();
    	SimpleDateFormat nowSdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        System.out.println(nowSdf.format(now));
        Calendar calendar = Calendar.getInstance();
        calendar.set(2013, 5, 4, 13, 44, 51);
        calendar.set(Calendar.YEAR, 2014);//年 
    	SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    	String nowTime = sdf.format(calendar.getTime());
    	System.out.println(nowTime);
        calendar.set(Calendar.MONTH, 7);//月（月份0代表1月） 
    	SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    	String nowTime1 = sdf1.format(calendar.getTime());
    	System.out.println(nowTime1);
        calendar.set(Calendar.DATE, 11);//日 
        calendar.set(Calendar.HOUR_OF_DAY, 15);//时 
        calendar.set(Calendar.MINUTE, 33);//分 
        calendar.set(Calendar.SECOND, 32);//秒 
    }

Dapatkan Isnin minggu ini, Isnin minggu lepas, Isnin minggu ini

    public static void main(String[] args) {
        //默认输出格式
    	Date now = new Date();
    	SimpleDateFormat nowSdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        System.out.println(nowSdf.format(now));
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(now);
    	calendar.add(Calendar.YEAR, 1);//年 
    	calendar.add(Calendar.MONTH, 1);//月 
    	calendar.add(Calendar.DATE, 1);//日 
    	//calendar.add(Calendar.DAY_OF_YEAR, 1);//今年的第 N 天
    	//calendar.add(Calendar.DAY_OF_MONTH, 1); // 本月第 N 天  
    	//calendar.add(Calendar.DAY_OF_WEEK, 1);// 本周几  
    	calendar.add(Calendar.HOUR_OF_DAY, -1);//时 
    	calendar.add(Calendar.MINUTE, 1);//分 
    	calendar.add(Calendar.SECOND, 1);//秒 
        //calendar.add(calendar.WEEK_OF_MONTH, 1);//增加一个礼拜
        //calendar.add(calendar.WEEK_OF_YEAR,1);//增加一个礼拜
       	SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    	String nowTime1 = sdf1.format(calendar.getTime());
    	System.out.println(nowTime1);
    }

Pengiraan hari

Kelas Penggunaan Tarikh untuk mengira perbezaan tarikh

    public static void main(String[] args) {
        //默认输出格式
    	Date now = new Date();
    	SimpleDateFormat nowSdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    	Calendar calendar = Calendar.getInstance();   
    	int firstD = calendar.getActualMinimum(calendar.DAY_OF_MONTH);   
    	int lastD = calendar.getActualMaximum(calendar.DAY_OF_MONTH);   
    	System.out.println("获取本月的第一天和最后天：" + firstD +"," + lastD);
    }

    public static Date geLastWeekMonday(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(getThisWeekMonday(date));
        cal.add(Calendar.DATE, -7);
        return cal.getTime();
    }
    public static Date getThisWeekMonday(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        // 获得当前日期是一个星期的第几天
        int dayWeek = cal.get(Calendar.DAY_OF_WEEK);
        if (1 == dayWeek) {
            cal.add(Calendar.DAY_OF_MONTH, -1);
        }
        // 设置一个星期的第一天，按中国的习惯一个星期的第一天是星期一
        cal.setFirstDayOfWeek(Calendar.MONDAY);
        // 获得当前日期是一个星期的第几天
        int day = cal.get(Calendar.DAY_OF_WEEK);
        // 根据日历的规则，给当前日期减去星期几与一个星期第一天的差值
        cal.add(Calendar.DATE, cal.getFirstDayOfWeek() - day);
        return cal.getTime();
    }
    public static Date getNextWeekMonday(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(getThisWeekMonday(date));
        cal.add(Calendar.DATE, 7);
        return cal.getTime();
    }
    public static void main(String[] args) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        try {
            Date date = sdf.parse("2017-09-10");
            System.out.println("今天是" + sdf.format(date));
            System.out.println("上周一" + sdf.format(geLastWeekMonday(date)));
            System.out.println("本周一" + sdf.format(getThisWeekMonday(date)));
            System.out.println("下周一" + sdf.format(getNextWeekMonday(date)));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

Kelas alat tarikh

public static void main(String[] args) {
	 Calendar love = Calendar.getInstance();  
     Calendar now = Calendar.getInstance();  
     love.set(2016, 8, 6); //真实的日期是2016-9-6;
     int days = (int) ((now.getTimeInMillis() - love.getTimeInMillis()) / (24 * 60 * 60 * 1000.0));  
     System.out.println(days); 
}

rrree

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