//问题:Calendar 到底是不是单例模式? Date类

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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falseCalendar 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());}}

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