java 用Calendar和GregorianCalendar，编写代码 显示年月日，时分秒，怎么写

Question

rt

Answer 1

import java.util.Calendar;
import java.util.GregorianCalendar;

public class TimeDemo {

public static void main(String[] args) {
Thread thread = new Thread(new ReadTime());
thread.start();
}

}

class ReadTime implements Runnable {
// Calendar和GregorianCalendar
public void run() {
try {
while (true) {
Thread.sleep(1000);
getTimeUseCalendar();
getTimeUseGregorianCalendar();
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}

public void getTimeUseCalendar() {
Calendar calendar = Calendar.getInstance();
System.out.println("Calendar time:" + calendar.get(Calendar.YEAR) + "-"
+ calendar.get(Calendar.MONTH) + "-"
+ calendar.get(Calendar.DAY_OF_MONTH) + " "
+ calendar.get(Calendar.HOUR_OF_DAY) + ":"
+ calendar.get(Calendar.MINUTE) + ":"
+ calendar.get(Calendar.SECOND));
}

public void getTimeUseGregorianCalendar() {
Calendar calendar = GregorianCalendar.getInstance();
System.out.println("GregorianCalendar time:"
+ calendar.get(Calendar.YEAR) + "-"
+ calendar.get(Calendar.MONTH) + "-"
+ calendar.get(Calendar.DAY_OF_MONTH) + " "
+ calendar.get(Calendar.HOUR_OF_DAY) + ":"
+ calendar.get(Calendar.MINUTE) + ":"
+ calendar.get(Calendar.SECOND));
}

}

Answer 2

使用SimpleDateFormat格式化 calendar的getTime方法的返回值。

new

new SimpleDateFormat("yyyyMMdd hh:mm:ss").format(cal.getTime());

追问

初学java，不懂。。能帮我写出来了吗

追答Calendar calendar = Calendar.getInstance();
SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMdd hh:mm:ss");
String r = formatter.format(calendar.getTime());
System.out.println(r);

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