Question

我有一个线程打印从执行开始每秒经过的时间和另一个每十五秒打印一条消息的线程。第一个线程应该更新线程之间共享的时间变量，并且每次更新时间变量时都会通知其他线程读取时间变量。这就是我目前所拥有的：

public class PingPong implements Runnable
{ 
    private static final int REPETITIONS = 4;

String curName = "";
int currentTime = 0;

Thread t1;
Thread t2;

PingPong() {
    t1 = new Thread(this, "Admin");
    t1.start();

    t2 = new Thread(this, "Admin1");
    t2.start();

}

public void run () {
try {
curName = Thread.currentThread().getName();

if(curName.equals(t1.getName())){
    for (int i=1; i<REPETITIONS; i++) { 
         System.out.println(Thread.currentThread().getName() + ": " + i);
        Thread.sleep(1000);
        // System.out.println(Thread.currentThread().getName() + ":" + Thread.currentThread().getState());
        System.out.println(t1.getName());
        currentTime++;
    }
}
/*else if(curName == t2){
    System.out.println("Thread 2");
}*/
System.out.println(currentTime);    


} catch (InterruptedException e) {      
         return; // end this thread
}
}

public static void main(String[] args) {
  new PingPong();
}
}

我对线程很新，我不确定我是否正在实现我已经拥有的东西。另外，我不知道如何通知另一个线程。我觉得我现在不在正确的道路上。

如果有人有任何帮助，我们非常感谢！

Answer 1

试试这段代码：

class T1 extends Thread
{
   private SharedClass s;
   private int t;
   T1 (SharedClass s)
   {
      this.s = s;
   }

   public void run ()
   {
       while(true) {
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        s.setSharedTime (++t);
        System.out.println (t + " displayed by T1");
       }
   }
}

class T2 extends Thread {
    private SharedClass s;

       T2 (SharedClass s)
       {
          this.s = s;
       }

       public void run ()
       {
          while(true) { 
          int t;
          t = s.getSharedTime ();
          System.out.println (t + " displayed by T2 after 15 seconds.");
          }
       }
}

public class SharedClass {
private int time;
private boolean shareable = true;

public static void main(String[] args) {
    SharedClass s = new SharedClass ();
    new T1 (s).start ();
    new T2 (s).start ();
}
synchronized void setSharedTime (int c)
{
   while (!shareable)
      try
      {
         wait ();
      }
      catch (InterruptedException e) {}

   this.time = c;
   if(c%15==0)
   shareable = false;
   notify ();
}

synchronized int getSharedTime ()
{
   while (shareable)
      try
      {
         wait ();
      }
      catch (InterruptedException e) { }

   shareable = true;
   notify ();

   return time;
}
}

java中的线程是轻量级进程，由单个CPU共享。而且java语句也需要一些时间来执行。该程序不能保证在15秒的时间间隔内运行，但大约需要15秒。

Java通知其他线程

1 个答案: