java Calender类

1.Calender和Date相互转化

public static void main(String[] args) {
		// TODO Auto-generated method stub
		Calendar calendar = Calendar.getInstance();    //
		System.out.println(calendar.getTime()); // 实际上是调用Date  

                                     date=new Date()
		calendar.setTime(new Date());
		System.out.println(calendar.getTime());
	}

2.Calendar的基本用法：

public static void main(String[] args) {
		// TODO Auto-generated method stub
		Calendar calendar = Calendar.getInstance();    //获取calendar实例
	    System.out.println(calendar.get(Calendar.YEAR)); //分别输出calendar中的年月日
	    System.out.println(calendar.get(Calendar.MONTH));
	    System.out.println(calendar.get(Calendar.DATE));

	    calendar.set(2011, 1, 3);  //设置calendar的时间
	    System.out.println(calendar.getTime()); //输出设置后的时间

	    calendar.add(calendar.MONTH, 13);  //用add加，超过的单位会进一
	    System.out.println(calendar.getTime());
	    calendar.roll(calendar.MONTH, 13); //roll加，超过的单位不会进一
	    System.out.println(calendar.getTime());

	}
result：

2013
11
15
Thu Feb 03 00:15:22 CST 2011
Sat Mar 03 00:15:22 CST 2012
Tue Apr 03 00:15:22 CST 2012

3.Calendar的容错性

public static void main(String[] args) {
		// TODO Auto-generated method stub
		Calendar calendar = Calendar.getInstance();    //获取calendar实例
	    calendar.set(calendar.MONTH,12);    //超过的部分在上一级加一（11+12）在year++
	    System.out.println(calendar.getTime());  //正常  

	    calendar.setLenient(false);   //关闭容错性,11+12在month的范围之外，判断错误
	    calendar.set(calendar.MONTH	, 12);
	    System.out.println(calendar.getTime()); //错误

	}

4.set方法的延迟修改

public static void main(String[] args) {
		// TODO Auto-generated method stub
		Calendar calendar = Calendar.getInstance();    //获取calendar实例
	    calendar.set(2013, 7, 31);    //month计数从0开始，所以是2013-08-31
	    System.out.println(calendar.getTime());

	    calendar.set(calendar.MONTH, 8);   //设置为9月：2013-9-？  set延迟效应，具体时间还没确定，出现get时才确认
	   // System.out.println(calendar.getTime());   //这时get，那么为2013-10-01 因为没有2013-09-31

	    calendar.set(calendar.DATE, 5);           //如果上述get没有，这里就是设置date 为5
	    System.out.println(calendar.getTime());   //这时两个set起作用  2013-09-05
	}