我想cal.setTime (new Date());
在我的代码中使用来更新时间,但它不起作用。
import javax.swing.JOptionPane;
public class Exercise2b {
public void demo() {
String message1, message2;
int hour, minute, second;
Time dt = new Time();
hour = dt.getHour();
minute = dt.getMinute();
second = dt.getSecond();
message1 = "The clock is " + minute + " minutes over " + hour + " (+"
+ second + " seconds)";
message2 = dt.toString();
JOptionPane.showMessageDialog(null, message1);
JOptionPane.showMessageDialog(null, message2);
dt.update();
message2 = dt.toString();
JOptionPane.showMessageDialog(null, message2);
}
public static void main(String[] args) {
Exercise2b prog = new Exercise2b();
prog.demo();
}
}
import java.util.Calendar;
import java.util.Date;
public class Time {
private Calendar cal;
private int hour;
private int minute;
private int second;
public Time() {
cal = Calendar.getInstance();
this.hour = cal.get(Calendar.HOUR_OF_DAY);
this.minute = cal.get(Calendar.MINUTE);
this.second = cal.get(Calendar.SECOND);
}
public int getHour() {
return this.hour;
}
public int getMinute() {
return this.minute;
}
public int getSecond() {
return this.second;
}
public String toString() {
return hour + ":" + minute + ":" + second;
}
public void update() {
cal.setTime (new Date());
}
}