时间和日期
Date
public static void main(String[] args) {
//获取到当前时间
Date da = new Date();
System.out.println(da);
long time = System.currentTimeMillis();
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
long time2 = System.currentTimeMillis();
System.out.println(time2-time);
System.out.println(time);
System.out.println(time2);
//使用date构造器来完成时间的初始化
Date da2 = new Date(time2);
System.out.println(da2);
System.out.println();
if(da.before(da2)){
System.out.println("ok");
}
System.out.println(da.equals(da2));
System.out.println(da.getYear());
//System.currentTimeMillis();
System.out.println(da.getTime());
}
DateFormat
public static void main(String[] args) {
Date da = new Date();
System.out.println(da.toString());
- 将日期类型转化为字符串格式
//将获取到日期格式化成指定的格式
//yyyy-MM-dd HH:mm:ss 表示格式的意思, 年份yyyy 月份MM 日期小写的dd HH时 mm分 ss秒
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
String value = dateFormat.format(da);
System.out.println(value);
SimpleDateFormat dateFormat2 = new SimpleDateFormat("yyyy/MM/dd HH-mm-ss");
String value2 = dateFormat2.format(da);
System.out.println(value2);
/**
* 将字符串转化为日期
* 在网页上输入的是字符串。后台用于判断或者保存的时候要用日期格式
*/
String da2 = "2018/09/09 12-23-40";
try {
Date da3 = dateFormat2.parse(da2);
System.out.println(da3);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
Calender
用于获取具体的时间数据年、月(月份从0开始计算,使用时要加1)、日、时、分、秒
public static void main(String[] args) {
//对象创建很多种方式 new clone
Calendar c = Calendar.getInstance();
int value1 = c.get(Calendar.YEAR);
System.out.println(value1);
int value2 = c.get(Calendar.MONTH);
System.out.println(value2);
int value3 = c.get(Calendar.DATE);
System.out.println(value3);
int value4 = c.get(Calendar.HOUR);
System.out.println(value4);
int value5 = c.get(Calendar.MINUTE);
System.out.println(value5);
int value6 = c.get(Calendar.SECOND);
System.out.println(value6);
System.out.println(c.getTime());
Date da = new Date();
int value7 = da.getYear();
System.out.println(value2);
GregorianCalendar g = new GregorianCalendar();
boolean boo = g.isLeapYear(2008);
System.out.println(boo);
}