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1简单例子
package com.kungeek.tip; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; public class Test { public static void main(String[] args) throws Exception { //字符串转换日期格式 SimpleDateFormat fmtDateTime = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //得到日期格式对象 Date setDate = fmtDateTime.parse("2010-03-03 12:12:12"); //日期转换为字符串格式 String setStr = (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS")).format(setDate); System.out.println(setStr); // 完整显示日期时间 String str = (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS")).format(new Date()); System.out.println(str); // 创建 Calendar 对象 Calendar calendar = Calendar.getInstance(); // 初始化 Calendar 对象,但并不必要,除非需要重置时间 calendar.setTime(new Date()); // setTime 类似上面一行 // Date date = new Date(); // calendar.setTime(setDate); // 显示年份 int year = calendar.get(Calendar.YEAR); System.out.println("YEAR is = " + String.valueOf(year)); // 显示月份 (从0开始, 实际显示要加一) int MONTH = calendar.get(Calendar.MONTH); System.out.println("MONTH is = " + (MONTH + 1)); // 今年的第 N 天 int DAY_OF_YEAR = calendar.get(Calendar.DAY_OF_YEAR); System.out.println("DAY_OF_YEAR is = " + DAY_OF_YEAR); // 本月第 N 天 int DAY_OF_MONTH = calendar.get(Calendar.DAY_OF_MONTH); System.out.println("DAY_OF_MONTH = " + String.valueOf(DAY_OF_MONTH)); // 3小时以后 calendar.add(Calendar.HOUR_OF_DAY, 3); int HOUR_OF_DAY = calendar.get(Calendar.HOUR_OF_DAY); System.out.println("HOUR_OF_DAY + 3 = " + HOUR_OF_DAY); // 当前分钟数 int MINUTE = calendar.get(Calendar.MINUTE); System.out.println("MINUTE = " + MINUTE); // 15 分钟以后 calendar.add(Calendar.MINUTE, 15); MINUTE = calendar.get(Calendar.MINUTE); System.out.println("MINUTE + 15 = " + MINUTE); // 30分钟前 calendar.add(Calendar.MINUTE, -30); MINUTE = calendar.get(Calendar.MINUTE); System.out.println("MINUTE - 30 = " + MINUTE); // 格式化显示 str = (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SS")).format(calendar.getTime()); System.out.println("经过一些运算后现在时间是 :"+str); // 重置 Calendar 显示当前时间 calendar.setTime(new Date()); str = (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SS")).format(calendar.getTime()); System.out.println("重置 Calendar 显示当前时间 :"+str); // 创建一个 Calendar 用于比较时间 Calendar calendarNew = Calendar.getInstance(); // 设定为 5 小时以前,后者大,显示 -1 calendarNew.add(Calendar.HOUR, -5); System.out.println("时间比较:" + calendarNew.compareTo(calendar)); // 设定7小时以后,前者大,显示 1 calendarNew.add(Calendar.HOUR, +7); System.out.println("时间比较:" + calendarNew.compareTo(calendar)); // 退回 2 小时,时间相同,显示 0 calendarNew.add(Calendar.HOUR, -2); System.out.println("时间比较:" + calendarNew.compareTo(calendar)); } }
结果输出
2015-10-12 16:13:21:655
YEAR is = 2015
MONTH is = 10
DAY_OF_YEAR is = 285
DAY_OF_MONTH = 12
HOUR_OF_DAY + 3 = 19
MINUTE = 13
MINUTE + 15 = 28
MINUTE - 30 = 58
经过一些运算后现在时间是 :2015-10-12 18:58:21:655
重置 Calendar 显示当前时间 :2015-10-12 16:13:21:655
时间比较:-1
时间比较:1
时间比较:0
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原文地址:http://www.cnblogs.com/crazylqy/p/4871996.html