增加并打印一个月内的所有天数

Question

我已经开始编写一些代码，需要打印一个月内的所有日期，我可以通过每天添加一个来做到这一点，但必须有一种更短的方法，我错过了。这是我目前的代码。

我知道它不是最漂亮的，我想知道如何打印日期，同时它在一月份的每一天递增，而不必每次都不断地加 1，然后每次都打印。

public static void main(String [] args) {

Calendar calendar = Calendar.getInstance()
calendar.set.(Integer.parseInt(args[0]), Integer.parseInt(args[1]), Integer.parseInt(args[2]));

System.out.println(calendar.getTime());
calendar.add(Calendar.DATE, 1);
System.out.println(calendar.getTime());

}

}

Answer 1

使用 Java 8 本地日期的简单示例，假设问题中的输入

import java.time.LocalDate;

public class Test
{
    public static void main(String[] args)
    {
        LocalDate ld = LocalDate.of(Integer.parseInt(args[0]), Integer.parseInt(args[1]), Integer.parseInt(args[2]));
        do {
            System.out.println(ld.toString());
            ld = ld.plusDays(1);
        } while (ld.getDayOfMonth() > 1);  // arive at 1st of next month
    }
}   

Answer 2

这里有一个简单的例子，它打印了一个月中的所有天数。时间部分已设置为零。

在这里，我们打印了 2016 年 3 月的所有日子。

Tue Mar 01 00:00:00 MST 2016
Wed Mar 02 00:00:00 MST 2016
Thu Mar 03 00:00:00 MST 2016
Fri Mar 04 00:00:00 MST 2016
Sat Mar 05 00:00:00 MST 2016
Sun Mar 06 00:00:00 MST 2016
Mon Mar 07 00:00:00 MST 2016
Tue Mar 08 00:00:00 MST 2016
Wed Mar 09 00:00:00 MST 2016
Thu Mar 10 00:00:00 MST 2016
Fri Mar 11 00:00:00 MST 2016
Sat Mar 12 00:00:00 MST 2016
Sun Mar 13 00:00:00 MST 2016
Mon Mar 14 00:00:00 MDT 2016
Tue Mar 15 00:00:00 MDT 2016
Wed Mar 16 00:00:00 MDT 2016
Thu Mar 17 00:00:00 MDT 2016
Fri Mar 18 00:00:00 MDT 2016
Sat Mar 19 00:00:00 MDT 2016
Sun Mar 20 00:00:00 MDT 2016
Mon Mar 21 00:00:00 MDT 2016
Tue Mar 22 00:00:00 MDT 2016
Wed Mar 23 00:00:00 MDT 2016
Thu Mar 24 00:00:00 MDT 2016
Fri Mar 25 00:00:00 MDT 2016
Sat Mar 26 00:00:00 MDT 2016
Sun Mar 27 00:00:00 MDT 2016
Mon Mar 28 00:00:00 MDT 2016
Tue Mar 29 00:00:00 MDT 2016
Wed Mar 30 00:00:00 MDT 2016
Thu Mar 31 00:00:00 MDT 2016

此代码适用于 Java 6、Java 7 和 Java 8。

package com.ggl.testing;

import java.util.Calendar;

public class PrintMonth {

    public static void main(String[] args) {

        Calendar calendar = Calendar.getInstance();

        if (args.length == 2) {
            int year = Integer.parseInt(args[0]);
            int month = Integer.parseInt(args[1]);
            calendar.set(year, month, 1);
        }

        int month = calendar.get(Calendar.MONTH);
        calendar.set(Calendar.DAY_OF_MONTH, 1);
        calendar.set(Calendar.HOUR_OF_DAY, 0);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        calendar.set(Calendar.MILLISECOND, 0);

        while (calendar.get(Calendar.MONTH) == month) {
            System.out.println(calendar.getTime());
            calendar.add(Calendar.DATE, 1);
        }

    }

}

Answer 3

public static void main(String[] args) {
        LocalDate date = LocalDate.of(Integer.parseInt(args[0]), Integer.parseInt(args[1]), 1);

        for (int i = 0; i < date.lengthOfMonth(); i++) {
            System.out.println(date);
            date = date.plusDays(1);
        }

    }

Answer 4

这是一个工作示例：

https://github.com/OpenGamma/OG-Platform/blob/master/projects/OG-Util/src/main/java/com/opengamma/util/time/LocalDateRange.java#L113

  public static LocalDateRange of(LocalDate startDateInclusive, LocalDate endDate, boolean endDateInclusive) {
    ArgumentChecker.notNull(startDateInclusive, "startDate");
    ArgumentChecker.notNull(endDate, "endDate");
    if (endDateInclusive == false && endDate.isBefore(LocalDate.MAX)) {
      endDate = endDate.minusDays(1);
    }
    if (endDate.isBefore(startDateInclusive)) {
      throw new IllegalArgumentException("Start date must be on or after end date");
    }
    return new LocalDateRange(startDateInclusive, endDate);
  }

Answer 5

这个例子怎么样？

@JRubyMethod(name = {"asctime", "ctime"})
    public RubyString asctime() {
        DateTimeFormatter simpleDateFormat;

        if (dt.getDayOfMonth() < 10) {
            simpleDateFormat = ONE_DAY_CTIME_FORMATTER;
        } else {
            simpleDateFormat = TWO_DAY_CTIME_FORMATTER;
        }
        String result = simpleDateFormat.print(dt);
        return getRuntime().newString(result);
    }

完整来源：http://code.openhub.net/file?fid=VJqxO5av-KgtoQFAp9juIzamnTc&cid=KOJoiAJBzj4&s=Increment%20and%20print%20all%20days%20in%20a%20month&pp=0&fl=Java&ff=1&filterChecked=true&fp=144796&mp,=1&ml=0&me=1&md=1&projSelected=true#L0