Java.util.GregorianCalendar.computeTime() 方法 Java.util.GregorianCalendar.computeFields() 方法 Java.util.EnumSet.clone() 方法 Java.util.GregorianCalendar.computeTime() 方法 package com.codingdict; import java.util.*; public class GregorianCalendarDemo extends GregorianCalendar { public static void main(String[] args) { // create a new calendar GregorianCalendarDemo cal = new GregorianCalendarDemo(); // print the current date and time System.out.println("" + cal.getTime()); // set a new year cal.set(GregorianCalendar.YEAR, 1992); System.out.println("" + cal.getTime()); // compute time and print the date cal.computeTime(); System.out.println("" + cal.getTime()); } } Java.util.GregorianCalendar.computeFields() 方法 Java.util.EnumSet.clone() 方法