Java 日期时间

Date( )

Date(long millisec)

实例

import java.util.Date;
  
public class DateDemo {
   public static void main(String args[]) {
       // 初始化 Date 对象
       Date date = new Date();
       
       // 使用 toString() 函数显示日期时间
       System.out.println(date.toString());
   }
}

Mon May 04 09:51:52 CDT 2013

实例

import java.util.*;
import java.text.*;

public class DateDemo {
   public static void main(String args[]) {

      Date dNow = new Date( );
      SimpleDateFormat ft =
      new SimpleDateFormat ("E yyyy.MM.dd 'at' hh:mm:ss a zzz");

      System.out.println("Current Date: " + ft.format(dNow));
   }
}

Current Date: Sun 2004.07.18 at 04:14:09 PM PDT

实例

import java.util.Date;

public class DateDemo {

  public static void main(String args[]) {
     // 初始化 Date 对象
     Date date = new Date();

     // 使用toString()显示日期和时间
     String str = String.format("Current Date/Time : %tc", date );

     System.out.printf(str);
  }
}

Current Date/Time : Sat Dec 15 16:37:57 MST 2012

实例

import java.util.Date;
  
public class DateDemo {

   public static void main(String args[]) {
       // 初始化 Date 对象
       Date date = new Date();
       
       // 使用toString()显示日期和时间
       System.out.printf("%1$s %2$tB %2$td, %2$tY",
                         "Due date:", date);
   }
}

Due date: February 09, 2004

实例

import java.util.Date;
  
public class DateDemo {

   public static void main(String args[]) {
       // 初始化 Date 对象
       Date date = new Date();
       
       // 显示格式化时间
       System.out.printf("%s %tB %<te, %<tY",
                         "Due date:", date);
   }
}

Due date: February 09, 2004

实例

import java.util.*;
import java.text.*;
  
public class DateDemo {

   public static void main(String args[]) {
      SimpleDateFormat ft = new SimpleDateFormat ("yyyy-MM-dd");

      String input = args.length == 0 ? "1818-11-11" : args[0];

      System.out.print(input + " Parses as ");

      Date t;

      try {
          t = ft.parse(input);
          System.out.println(t);
      } catch (ParseException e) {
          System.out.println("Unparseable using " + ft);
      }
   }
}

$ java DateDemo
1818-11-11 Parses as Wed Nov 11 00:00:00 GMT 1818
$ java DateDemo 2007-12-01
2007-12-01 Parses as Sat Dec 01 00:00:00 GMT 2007

实例

import java.util.*;
  
public class SleepDemo {
   public static void main(String args[]) {
      try {
         System.out.println(new Date( ) + "\n");
         Thread.sleep(1000*3);   // 休眠3秒
         System.out.println(new Date( ) + "\n");
      } catch (Exception e) {
          System.out.println("Got an exception!");
      }
   }
}

Thu Sep 17 10:20:30 CST 2015

Thu Sep 17 10:20:33 CST 2015

实例

import java.util.*;
  
public class DiffDemo {

   public static void main(String args[]) {
      try {
         long start = System.currentTimeMillis( );
         System.out.println(new Date( ) + "\n");
         Thread.sleep(5*60*10);
         System.out.println(new Date( ) + "\n");
         long end = System.currentTimeMillis( );
         long diff = end - start;
         System.out.println("Difference is : " + diff);
      } catch (Exception e) {
         System.out.println("Got an exception!");
      }
   }
}

Fri Jan 08 09:48:47 CST 2016

Fri Jan 08 09:48:50 CST 2016

Difference is : 3019

Calendar c = Calendar.getInstance();//默认是当前日期

//创建一个代表2009年6月12日的Calendar对象
Calendar c1 = Calendar.getInstance();
c1.set(2009, 6 - 1, 12);

Calendar c1 = Calendar.getInstance();

public final void set(int year,int month,int date)

c1.set(2009, 6 - 1, 12);//把Calendar对象c1的年月日分别设这为：2009、6、12

public void set(int field,int value)

c1.set(Calendar.DATE,10);

c1.set(Calendar.YEAR,2008);

Calendar c1 = Calendar.getInstance();

c1.add(Calendar.DATE, 10);

c1.add(Calendar.DATE, -10);

Calendar c1 = Calendar.getInstance();
// 获得年份
int year = c1.get(Calendar.YEAR);
// 获得月份
int month = c1.get(Calendar.MONTH) + 1;
// 获得日期
int date = c1.get(Calendar.DATE);
// 获得小时
int hour = c1.get(Calendar.HOUR_OF_DAY);
// 获得分钟
int minute = c1.get(Calendar.MINUTE);
// 获得秒
int second = c1.get(Calendar.SECOND);
// 获得星期几（注意（这个与Date类是不同的）：1代表星期日、2代表星期1、3代表星期二，以此类推）
int day = c1.get(Calendar.DAY_OF_WEEK);

实例

import java.util.*; public class GregorianCalendarDemo {

   public static void main(String args[]) {
      String months[] = {
      "Jan", "Feb", "Mar", "Apr",
      "May", "Jun", "Jul", "Aug",
      "Sep", "Oct", "Nov", "Dec"};
     
      int year;
      // 初始化 Gregorian 日历
      // 使用当前时间和日期
      // 默认为本地时间和时区
      GregorianCalendar gcalendar = new GregorianCalendar();
      // 显示当前时间和日期的信息
      System.out.print("Date: ");
      System.out.print(months[gcalendar.get(Calendar.MONTH)]);
      System.out.print(" " + gcalendar.get(Calendar.DATE) + " ");
      System.out.println(year = gcalendar.get(Calendar.YEAR));
      System.out.print("Time: ");
      System.out.print(gcalendar.get(Calendar.HOUR) + ":");
      System.out.print(gcalendar.get(Calendar.MINUTE) + ":");
      System.out.println(gcalendar.get(Calendar.SECOND));
     
      // 测试当前年份是否为闰年
      if(gcalendar.isLeapYear(year)) {
         System.out.println("当前年份是闰年");
      }
      else {
         System.out.println("当前年份不是闰年");
      }
   }
}

Date: Apr 22 2009
Time: 11:25:27
当前年份不是闰年