1. 获取当期日期、年份、月份
- import java.util.Calendar;
- public class Main {
- public static void main(String[] args) {
- Calendar now = Calendar.getInstance();
- System.out.println("Current Year is : " + now.get(Calendar.YEAR));
- // month start from 0 to 11
- System.out.println("Current Month is : " + (now.get(Calendar.MONTH) + 1));
- System.out.println("Current Date is : " + now.get(Calendar.DATE));
- }
- }
2. 获取前一天、前一个月的日期
- Calendar calendar = Calendar.getInstance();//此时打印它获取的是系统当前时间
- calendar.add(Calendar.DATE, -1); //得到前一天
- String yestedayDate = new SimpleDateFormat("yyyy-MM-dd").format(cal.getTime());
- calendar.add(Calendar.MONTH, -1); //得到前一个月
- int year = calendar.get(Calendar.YEAR);
- int month = calendar.get(Calendar.MONTH)+1; //输出前一月的时候要记得加1
3. 字符串转为日期格式
- String date = "2010-02-01 23:59:59";
- SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
- try {
- Date d = sf.parse(date);
- System.out.println(sf.format(d));
- } catch (ParseException e) {
- e.printStackTrace();
- }
4.完整的一个例子
- import java.util.Date;
- import java.util.Calendar;
- import java.text.SimpleDateFormat;
- public class TestDate{
- public static void main(String[] args){
- Date now = new Date();
- SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");//可以方便地修改日期格式
- String hehe = dateFormat.format( now );
- System.out.println(hehe);
- Calendar c = Calendar.getInstance();//可以对每个时间域单独修改
- int year = c.get(Calendar.YEAR);
- int month = c.get(Calendar.MONTH);
- int date = c.get(Calendar.DATE);
- int hour = c.get(Calendar.HOUR_OF_DAY);
- int minute = c.get(Calendar.MINUTE);
- int second = c.get(Calendar.SECOND);
- System.out.println(year + "/" + month + "/" + date + " " +hour + ":" +minute + ":" + second);
- }
- }