javacalendarJava中日历类（CalendarClass）的用途？

java如何通过calendar类获取当前系统日期

Calendar ca = Calendar.getInstance(); int year = ca.get(Calendar.YEAR);//获取年份 int month=ca.get(Calendar.MONTH);//获取月份 int day=ca.get(Calendar.DATE);//获取日 int minute=ca.get(Calendar.MINUTE);//分 int hour=ca.get(Calendar.HOUR);//小时 int second=ca.get(Calendar.SECOND);//秒 int WeekOfYear = ca.get(Calendar.DAY_OF_WEEK);

java中的Calendar如何使用的？

package pack.java.calendar.demo; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; public class CalendarDemo { private static SimpleDateFormat date_format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss"); public static void main(String[] args) { //获取calendar实例; Calendar calendar = Calendar.getInstance(); //判断calendar是不是GregorianCalendar类的实例; if(calendar instanceof GregorianCalendar){ System.out.println("属于GregorianCalendar类的实例!"); } //从calendar对象中获得date对象，当前时间; Date dates = calendar.getTime(); //格式化时间; String date_str= date_format.format(dates); System.out.println(date_str); //设置月份05；代表日历的月份6月，因为月份从0开始。

calendar.set(Calendar.MONTH, 05); int months = calendar.get(Calendar.MONTH); System.out.println(months); //输出05; //设置日期为2011-07-24 09：59:50 calendar.set(2011, 06, 24, 9, 59, 50); String getDate = date_format.format(calendar.getTime()); System.out.println(getDate); //输出2011-07-24 09:59:50; //比较日前大小; if(new Date().getTime() > calendar.getTimeInMillis()){ System.out.println("当前日期在后!"); }else{ System.out.println("当前日期在前!"); } //设置当前时间为:2011-07-24 11:06:00 calendar.setTime(new Date()); int year = calendar.get(Calendar.YEAR); //获取年; int month = calendar.get(Calendar.MONTH); //获取月; int date = calendar.get(Calendar.DATE); //获取天; int hour = calendar.get(Calendar.HOUR); //获取小时; int minute = calendar.get(Calendar.MINUTE); //获取分钟; int second = calendar.get(Calendar.SECOND); //获取秒钟; int hour_of_day = calendar.get(Calendar.HOUR_OF_DAY); //第几个小时， int day_of_month = calendar.get(Calendar.DAY_OF_MONTH); //这天，在一个月内是第几天. int day_of_week = calendar.get(Calendar.DAY_OF_WEEK); //这天，在一周内，是第几天. int day_of_year = calendar.get(Calendar.DAY_OF_YEAR); //这天，在一年内，是第几天。

int week_of_year = calendar.get(Calendar.WEEK_OF_YEAR); //这周，在一年内是第几周; int week_of_month = calendar.get(Calendar.WEEK_OF_MONTH);//这周，在这个月是第几周;以以星为标准； int zone_offset = calendar.get(Calendar.ZONE_OFFSET); //获取时区; int day_of_week_in_month = calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH); //某月中第几周，按这个月1号算，1号起就是第1周，8号起就是第2周。

以月份天数为标准 int r = calendar.get(Calendar.AM_PM); if(r==calendar.AM){ System.out.println("现在是上午"); } if(r==calendar.PM){ System.out.println("现在是下午"); } System.out.println("=================================================="); System.out.println(year); System.out.println(month); System.out.println(date); System.out.println(hour); System.out.println(minute); System.out.println(second); System.out.println(hour_of_day); System.out.println(day_of_month); System.out.println(day_of_week); System.out.println(day_of_year); System.out.println(week_of_year); System.out.println(week_of_month); System.out.println(zone_offset); System.out.println(day_of_week_in_month); } }

如何用JAVA编写出一个简单的日历

import javax.swing.JOptionPane; public class NewClass{ public static void main(String[] args){ int year,month; Calender cal=new Calender(2008,10); cal.showCalender(); year=Integer.parseInt(JOptionPane.showInputDialog("Year:")); month=Integer.parseInt(JOptionPane.showInputDialog("Month:")); cal.setYear(year); cal.setMonth(month); cal.showCalender(); } } class Calender{ private int year,month; public Calender(){ year=0; month=1; } public Calender(int year){ this.year=year; month=1; } public Calender(int year,int month){ this.year=year; if(month>12) this.month=month%12; else this.month=month; } public void setYear(int year){ this.year=year; } public void setMonth(int month){ if(month>12) this.month=month%12; else this.month=month; } private int dayOfMonth(){ int days=0; switch(month){ case 1:days=31;break; case 2:{ if(((year%4==0)&&(year%100!=0))||(year%400==0)) days=29; else days=28; break; } case 3:days=31;break; case 4:days=30;break; case 5:days=31;break; case 6:days=30;break; case 7:days=31;break; case 8:days=31;break; case 9:days=30;break; case 10:days=31;break; case 11:days=30;break; case 12:days=31;break; default: days=0; } return days; } private int dayOfWeek(){ int Y=year; int M=month; int D=1; int A; A = Y>0?(5+(Y+1)+(Y-1)/4-(Y-1)/100+(Y-1)/400)%7:(5+Y+Y/4-Y/100+Y/400)%7; A = M>2?(A+2*(M+1)+3*(M+1)/5)%7:(A+2*(M+2)+3*(M+2)/5)%7; if (((Y%4 == 0 && Y%100 != 0)|| Y%400 == 0) && M>2) A =(A+1)%7; A=(A+D)%7; return A; } public void showCalender(){ String str=new String(); str=" "; str+=year+"年"+month+"月"; str+=" "; str+="日 一 二 三 四 五 六 "; int week=this.dayOfWeek(); for(int i=0,j=1;i<7;i++){ if(i<week) str+=" "; else{ str+=" "+j+" "; j++; } } str+=" "; end: for(int i=7-week+1;i<=this.dayOfMonth();){ for(int j=0;j<7;j++){ if(i<10) str+=" "+i+" "; else str+=i+" "; i++; if(i>this.dayOfMonth()) break end; } str+=" "; } JOptionPane.showMessageDialog(null,str); } } 用一个类来实现

Java中日历类（CalendarClass）的用途？

Java中日历类（Calendar类）的用途如下： ????Calendar类的静态方法getInstance()可以初始化一个日历对象:Calendar now = ????????Calendar.getInstance(); ? ? ????可以使用下面三个方法把日历定到任何一个时间： ?????set(int?year?,int?month,int?date)??; ?????set(int?year?,int?month,int?date,int?hour,int?minute)?; ?????set(int?year?,int?month,int?date,int?hour,int?minute,int?second)?;????如果想获得年份、月份、小时等信息可以使用： ? ??????Now.get(Calendar.Month);//这样的方法?0表示一月，1表示二月?? ?????get(Calendar.DAY_OF_MONTH);//获得这个月的第几天 ?????get(Calendar.DAY_OF_WEEK);//获得这个星期的第几天? ?????get(Calendar.DAY_OF_YEAR);//获得这个年的第几天?? ???????getTimeMillis();//获得当前时间的毫秒表示 ????1.计算某一月份的最大天数 ????Calendar?time=Calendar.getInstance();? ????time.clear();? ????time.set(Calendar.YEAR,year);? ????time.set(Calendar.MONTH,i-1);//注意,Calendar对象默认一月为0????????????? ????int?day=time.getActualMaximum(Calendar.DAY_OF_MONTH);//本月份的天数 ????注：在使用set方法之前，必须先clear一下，否则很多信息会继承自系统当前时间 ????2.Calendar和Date的转化 ????(1) Calendar转化为Date ????Calendar?cal=Calendar.getInstance(); ????Date?date=cal.getTime(); ????(2) Date转化为Calendar ????Date?date=new?Date(); ????Calendar?cal=Calendar.getInstance(); ????cal.setTime(date); ????3.格式化输出日期时间 ????Date?date=new?Date(); ????SimpleDateFormat?df=new?SimpleDateFormat("yyyy-MM-dd?hh:mm:ss"); ????System.out.println(df.format(date)); ????4.计算相隔天数的方法 ????public?int?getDaysBetween?(Calendar?d1,?Calendar?d2){ ??????if?(d1.after(d2)){??//?swap?dates?so?that?d1?is?start?and?d2?is?end ???????????java.util.Calendar?swap?=?d1; ???????????d1?=?d2; ???????????d2?=?swap; ??????} ??????int?days?=?d2.get(Calendar.DAY_OF_YEAR)?-?d1.get(Calendar.DAY_OF_YEAR); ??????int?y2?=?d2.get(Calendar.YEAR); ?????if?(d1.get(Calendar.YEAR)?!=?y2){ ???????????d1?=?(Calendar)?d1.clone(); ???????????do{ ?????????????days?+=?d1.getActualMaximum(Calendar.DAY_OF_YEAR);//得到当年的实际天数 ???????????????d1.add(Calendar.YEAR,?1); ??????????}?while?(d1.get(Calendar.YEAR)?!=?y2); ??????} ???????return?days; ????}