java中使用线程实现Timer（定时器）原理和源码

下载源码和示例

1 原理：启动一个线程来刷时间，缺点是不太精确，可能跟线程的优先级有关系。

会有0-10ms的误差。精确到0.1s是没有问题的。

 

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);
    
    }

}