Question

Java用Calendar如何每秒取一次系统时间

Answer 1

用线程可以啊

import java.util.*;

public class test implements Runnable{

Thread th0 ;
//public void run(){}
public test(Thread th)
{
th0 = th;
th0= new Thread(this);
th0.start();
}

public void run()
{
try{

while(true)
{
if(Thread.currentThread()==th0){
Calendar cal = Calendar.getInstance();
int wd = cal.get(Calendar.DAY_OF_WEEK);
String x = "";
switch(wd){
case 1:x="星期日";break;
case 2:x="星期一";break;
case 3:x="星期二";break;
case 4:x="星期三";break;
case 5:x="星期四";break;
case 6:x="星期五";break;
case 7:x="星期六";break;
}
int y = cal.get(Calendar.YEAR);
int mon = cal.get(Calendar.MONTH)+1;
int d = cal.get(Calendar.DATE);
int h = cal.get(Calendar.HOUR);
int min = cal.get(Calendar.MINUTE);
int s = cal.get(Calendar.SECOND);
int ap = cal.get(Calendar.AM_PM);
if(ap==1)
h = h+12;
StringBuffer sb = new StringBuffer("日期："+y+"-"+((mon<=9)?"0"+mon:mon)+"-"+((d<=9)?"0"+d:d)+" 时间："+h+":"+((min<=9)?"0"+min:min)+":"+((s<=9)?"0"+s:s)+" "+x);

System.out.println(sb);

Thread.sleep(1000);
}
}
}catch(Exception ee){
ee.getStackTrace();
}
}
public static void main(String[] args) {
Thread th = new Thread();
test t = new test(th);
t.run();
}
}

Answer 2

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Timer;

public class MainTest {

public static void main(String[] args) {

Timer timer=new Timer();
MyTimerTask task=new MyTimerTask();
timer.schedule(task, new Date(), 1000);
}
}

class MyTimerTask extends java.util.TimerTask {
String now;
public void run() {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
now=sdf.format(new Date());
System.out.println(now);

}

public String getNow(){
return this.now;
}

}

Answer 3

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Timer;

public class MainTest {

public static void main(String[] args) {

Timer timer=new Timer();
MyTimerTask task=new MyTimerTask();
timer.schedule(task, new Date(), 1000);
}
}

class MyTimerTask extends java.util.TimerTask {
String now;
public void run() {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
now=sdf.format(new Date());
System.out.println(now);

}

public String getNow(){
return this.now;
}

}

Answer 4

1楼可以为
Calender aa = Calender.getI...;
Date d = aa.getTime();
system.out.print(d);