//问题:Calendar 到底是不是单例模式? Date类

import java.util.Calendar;
import java.util.Date;

public class DateDemo {
public static void main(String[] args) {
// Date date=new Date();
System.out.println(new Date());
long time = new Date().getTime();// 把年月日转化为毫秒,1s=1000ms 1秒=1000毫秒
System.out.println(time);

// 注意:下面一串数字默认为int类型,需要通过后加L强制转化为long类型才可以.
// 输出一个固定不变的时间
Date d = new Date(1441877203040L);// 把毫秒转化为年月日,
System.out.println(d);

// 比较时间的前后,返回的是boolean类型
System.out.println(new Date().after(d));
System.out.println(new Date().before(d));

// 问题:Calendar 到底是不是单例模式? 争议:1不能new 2 c1==c2为false
Calendar c1 = Calendar.getInstance();
Calendar c2 = Calendar.getInstance();
Runtime run1 = Runtime.getRuntime();
Runtime run2 = Runtime.getRuntime();
System.out.println("c1.equals(c2) is " + c1.equals(c2));
System.out.println("c1 == c2 is " + (c1 == c2));

System.out.println("run1.equals(run2) is " + run1.equals(run2));
System.out.println("run1 == run2 is " + (run1 == run2));
System.out.println(c1.getTime());
System.out.println(c2.getTime());

}
}