基础深化和提高-常用类

package com.tong; import java.util.*; public class TestCalendar { public static void main(String[ ] args) { // 得到相关日期元素 GregorianCalendar calendar = new GregorianCalendar (2049, 9, 1, 22, 10, 50); System.out.println(calendar); printCalendar(calendar); int year = calendar.get(Calendar.YEAR); // 打印：2049 int month = calendar.get(Calendar.MONTH); // 打印：10 int day = calendar.get(Calendar.DAY_OF_MONTH); // 打印：9 int day2 = calendar.get(Calendar.DATE); // 打印：9 // 日：Calendar.DATE和Calendar.DAY_OF_MONTH同义 int date = calendar.get(Calendar.DAY_OF_WEEK); // 打印：3 // 星期几 这里是：1-7.周日是1，周一是2，。。。周六是7 System.out.println(year); System.out.println(month); System.out.println(day); System.out.println(day2); System.out.println(date); // 设置日期 GregorianCalendar calendar2 = new GregorianCalendar(); calendar2.set(Calendar.YEAR, 2049); calendar2.set(Calendar.MONTH, Calendar.OCTOBER); // 月份数：0-11 calendar2.set(Calendar.DATE, 1); calendar2.set(Calendar.HOUR_OF_DAY, 10); calendar2.set(Calendar.MINUTE, 20); calendar2.set(Calendar.SECOND, 23); printCalendar(calendar2); // 日期计算 GregorianCalendar calendar3 = new GregorianCalendar(2049, 9, 1, 22, 10, 50); calendar3.add(Calendar.MONTH, -7); // 月份减7 calendar3.add(Calendar.DATE, 7); // 增加7天 printCalendar(calendar3); // 日历对象和时间对象转化 Date d = calendar3.getTime(); GregorianCalendar calendar4 = new GregorianCalendar(); calendar4.setTime(new Date()); } static void printCalendar(Calendar calendar) { int year = calendar.get(Calendar.YEAR); int month = calendar.get(Calendar.MONTH) + 1; int day = calendar.get(Calendar.DAY_OF_MONTH); int date = calendar.get(Calendar.DAY_OF_WEEK) - 1; // 星期几 String week = "" + ((date == 0) ? "日" : date); int hour = calendar.get(Calendar.HOUR); int minute = calendar.get(Calendar.MINUTE); int second = calendar.get(Calendar.SECOND); System.out.printf("%d年%d月%d日,星期%s %d:%d:%d\n", year, month, day, week, hour, minute, second); } }