Java的Thread测试[包括sleep,wait的使用比较]

package javaBese;

public class ThreadTest {

/*
* 共同点： 他们都是在多线程的环境下，都可以在程序的调用处阻塞指定的毫秒数，并返回。

   不同点： Thread.sleep(long)可以不在synchronized的块下调用，而且使用Thread.sleep()不会丢失当前线程对任何对象的同步锁(monitor);
                object.wait(long)必须在synchronized的块下来使用，调用了之后失去对object的monitor, 这样做的好处是它不影响其它的线程对object进行操作。
   */

public void thread()
{
   System.out.println("I am here!");
  
   Thread thread = new Thread();
   Thread thread2 = new Thread();
   try {
   
    thread2.sleep(1000);
    System.out.println("sleep 1秒后,I am come back!");
   
    thread2.start();
    System.out.println("thread is start");
   
    thread2.stop();
    System.out.println("thread is stop");
   
    synchronized (thread)//如果使用wait,就必须synchronized来同步对象
    {
     System.out.println("");
     for (int i = 0; i < 5; i++) {
      thread.notify();//必须要放在synchronized方法的里面
      System.out.println("First,notify thread");
      thread.wait(1000);
      System.out.println("wait 1秒后,I am come back!");
     }
    }
   } catch (Exception e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
}

public static void main(String[] args) {
   ThreadTest threadTest = new ThreadTest();
   threadTest.thread();
}

}

/*
* 复杂应用
程序会启动20个线程，20个线程都使用同一个sync的object（名字为SYNC）。 线程启动代码如下：

Java代码
final TC[] ts = new TC[20];  
        for (int i = 0; i < ts.length; i++) {  
            TC target = new TC("TC " + i, SYNC1);  
            Thread thread = new Thread(target);  
            ts[i] = target;  
            thread.start();  
}

final TC[] ts = new TC[20];
        for (int i = 0; i < ts.length; i++) {
            TC target = new TC("TC " + i, SYNC1);
            Thread thread = new Thread(target);
            ts[i] = target;
            thread.start();
}
------------------------------------------------------------
接下来马上启动另外一个线程用于做notify操作。

Java代码
// 一个用于停止的Thread  
        new Thread(new Runnable() {  
            public void run() {  
                synchronized (SYNC1) {  
                    int i = 10;  
                    while (i > 0) {  
                        System.out.println("Now will notify the thread " + i);  
                        ts[i].notifySelf();  
                        try {  
                            SYNC1.wait(10000);  
                        } catch (InterruptedException e) {  
                            e.printStackTrace();  
                        }  
                        i--;  
                    }  
                }  
            }  
}).start();

// 一个用于停止的Thread
        new Thread(new Runnable() {
            public void run() {
                synchronized (SYNC1) {
                    int i = 10;
                    while (i > 0) {
                        System.out.println("Now will notify the thread " + i);
                        ts[i].notifySelf();
                        try {
                            SYNC1.wait(10000);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                        i--;
                    }
                }
            }
}).start();

------------------------------------------------------------

Java代码
启动的ＴＣ线程代码如下：  

class TC implements Runnable {  

    private final String name;  

    private final Object sync;  

    private boolean isRunning = false;  

    public TC(String name, Object sync) {  
        this.name = name;  
        this.sync = sync;  
    }  

    public void run() {  
        synchronized (sync) {  
            while (true) {  
                // 每个线程默认都加入线程池排队。这样有助于打乱线程在主线程中启动的顺序，方便后面的观测。  
                if (!isRunning) {  
                    try {  
                        sync.wait(1000);  
                    } catch (InterruptedException e) {  
                        e.printStackTrace();  
                    }  
                    isRunning = true;  
                }  
                System.out.println(name + " Running .......");  
                try {  
                    sync.wait();  
                } catch (InterruptedException e) {  
                    e.printStackTrace();  
                }// Wait 1 second  
            }  
        }  
    }  

    public void notifySelf() {  
        synchronized (sync) {  
            System.out.println("Coming to notify the thread " + name);  
            sync.notify();  
        }  

    }  

}

启动的ＴＣ线程代码如下：

class TC implements Runnable {

    private final String name;

    private final Object sync;

    private boolean isRunning = false;

    public TC(String name, Object sync) {
        this.name = name;
        this.sync = sync;
    }

    public void run() {
        synchronized (sync) {
            while (true) {
                // 每个线程默认都加入线程池排队。这样有助于打乱线程在主线程中启动的顺序，方便后面的观测。
                if (!isRunning) {
                    try {
                        sync.wait(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    isRunning = true;
                }
                System.out.println(name + " Running .......");
                try {
                    sync.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }// Wait 1 second
            }
        }
    }

    public void notifySelf() {
        synchronized (sync) {
            System.out.println("Coming to notify the thread " + name);
            sync.notify();
        }

    }

}

---------------------------分割线---------------------------------

输出日志如下（//部分是我加的注释，不是实际输出）：

Now will notify the thread 10 //首先试着notify第10个TC
Coming to notify the thread TC 10 // 也确实调用了SYNC的notify操作，但是因为当前还没有任何线程在wait，所以这个notify信号就被丢弃掉了。这个notify过去就过去了。不会影响后面的任何操作了。
TC 1 Running .......
TC 5 Running .......
TC 0 Running .......
TC 2 Running .......
TC 4 Running .......
TC 6 Running .......
TC 8 Running .......
TC 10 Running .......
TC 12 Running .......
TC 14 Running .......
TC 7 Running .......
TC 9 Running .......
TC 11 Running .......
TC 13 Running .......
TC 15 Running .......
TC 17 Running .......
TC 3 Running .......
TC 18 Running .......
TC 16 Running .......
TC 19 Running ....... //启动20线程，这20个线程启动的顺序已经被打乱了。不会从头到尾1-20的启动，而是如log显示1,5,0,2,4,6,8,10,12,14.........
//每个线程启动后会被wait(). wait的顺序是1,5,0,2,4,6,8,10,12,14.........
Now will notify the thread 9
Coming to notify the thread TC 9
TC 1 Running .......
Now will notify the thread 8
Coming to notify the thread TC 8
TC 5 Running .......
Now will notify the thread 7
Coming to notify the thread TC 7
TC 0 Running .......
Now will notify the thread 6
Coming to notify the thread TC 6
TC 2 Running .......
Now will notify the thread 5
Coming to notify the thread TC 5
TC 4 Running .......
Now will notify the thread 4
Coming to notify the thread TC 4
TC 6 Running .......
Now will notify the thread 3
Coming to notify the thread TC 3
TC 8 Running .......
Now will notify the thread 2
Coming to notify the thread TC 2
TC 10 Running .......
Now will notify the thread 1
Coming to notify the thread TC 1
TC 12 Running .......
//总共10个notify操作，但是因为启动的时候一个notify因为没有任何wait的线程给丢弃了，所以，这里只有9个notify起到了作用。他们是按照进入pool的顺序排队给notify。
//一个notify操作仅仅激活一个wait队列中的第一个线程。一对一操作。

-------------------------------分割线------------------------------
使用notifyAll代替notify。

日志输出：

Now will notify the thread 10
Coming to notify the thread TC 10 //第一个notifyAll的操作还是被丢弃了
TC 0 Running .......
TC 1 Running .......
TC 3 Running .......
TC 5 Running .......
TC 7 Running .......
TC 9 Running .......
TC 11 Running .......
TC 13 Running .......
TC 15 Running .......
TC 17 Running .......
TC 19 Running .......
TC 2 Running .......
TC 4 Running .......
TC 6 Running .......
TC 8 Running .......
TC 10 Running .......
TC 12 Running .......
TC 14 Running .......
TC 16 Running .......
TC 18 Running .......
Now will notify the thread 9
Coming to notify the thread TC 9 //一个notifyAll的操作notify所以正在wait的线程。
TC 0 Running .......
TC 1 Running .......
TC 3 Running .......
TC 5 Running .......
TC 7 Running .......
TC 9 Running .......
TC 11 Running .......
TC 2 Running .......
TC 13 Running .......
TC 15 Running .......
TC 4 Running .......
TC 17 Running .......
TC 19 Running .......
TC 6 Running .......
TC 8 Running .......
TC 10 Running .......
TC 12 Running .......
TC 14 Running .......
TC 16 Running .......
TC 18 Running .......

* */

 

 

 

转自：http://hi.baidu.com/billgon/blog/item/503fb458997888cc9c820490.html