java中Calendar类

1.测试代码：

 package com;
 
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;
 
 /**
  * Created by huyanxia on 2017/9/30.
  */
 public class calendarTest {
     public static void main(String[] args) {
         Calendar calendar = Calendar.getInstance();
         Date date = new Date();
         calendar.setTime(date);
         int day = calendar.get(Calendar.DAY_OF_YEAR);
         int month = calendar.get(Calendar.DAY_OF_MONTH);
         int second = calendar.get(Calendar.SECOND);
         int maxdays = calendar.getActualMaximum(Calendar.DAY_OF_YEAR);
         int mindays = calendar.getActualMinimum(Calendar.DAY_OF_YEAR);
         int maxmonths = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
         int minmonths = calendar.getActualMinimum(Calendar.DAY_OF_MONTH);
         //int day = calendar.get(Calendar.DAY_OF_YEAR);
         SimpleDateFormat simpleDateFormat = new SimpleDateFormat("YYYY-MM-dd-HH-mm-ss");
         System.out.println("现在时间"+simpleDateFormat.format(date));
         System.out.println("今天是2017年的第几天："+day);
         System.out.println("今天是2017年的9月第几天："+month);
         System.out.println("当前的秒数："+second);
         System.out.println("今年天数最大值："+maxdays);
         System.out.println("今年天数最小值："+mindays);
         System.out.println("月份最大值："+maxmonths);
         System.out.println("月份最小值："+minmonths);
     }
 }

结果：

注意：格式化时，年月日时分秒：“YYYY-MM-dd-HH-mm-ss”（24小时制）

“YYYY-MM-dd-hh-mm-ss”（12小时制）