java中使用线程实现Timer（定时器）原理和源码
package timer;

public class Timer {

private long interval;

// private boolean enabled;
private Task task;

private Clock clock;

public Timer(long _interval, Task _task) {
super();
this.interval = _interval;
// this.enabled = enabled;
this.task = _task;

clock = new Clock();
clock.start();

new Thread(new Runnable() {

public void run() {

boolean b = true;

while (b) {

//System.out.println(clock.getCurrTime());

if (interval <= clock.getCurrTime()) {

System.out.println(clock.getCurrTime());

task.doit();
clock.setCurrTime(0);

//clock.stop();

//System.out.println(clock.getCurrTime());

//b = false;
}
}

}

}).start();

}

public Task getTask() {
return task;
}

public long getInterval() {
return interval;
}

// public boolean isEnabled() {
// return enabled;
// }
// public void setEnabled(boolean enabled) {
// this.enabled = enabled;
// }
}
package timer;

public class Clock extends Thread {

private long oldTime;

private long currTime;

public Clock() {
oldTime = System.currentTimeMillis();
currTime = 0;
}

public long getCurrTime() {
return currTime;
}

@Override
public void run() {

while (true) {
currTime = System.currentTimeMillis() - oldTime;
}

}

public void setCurrTime(long currTime) {
this.currTime = currTime;
}

}
package timer;

public interface Task {

void doit();
}
package timer;

public class NewTask implements Task {

public void doit() {
System.out.println( System.currentTimeMillis() );
}

}
package timer;

public class Test {

/**
* @param args
*/
public static void main(String[] args) {

Task task = new NewTask();
Timer t = new Timer(1000,task);

}

}