Question

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

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);