Java7并发编程实战（一） 线程的等待

试想一个情景，有两个线程同时工作，还有主线程，一个线程负责初始化网络，一个线程负责初始化资源，然后需要两个线程都执行完毕后，才能执行主线程

　　首先创建一个初始化资源的线程

　　

public class DataSourcesLoader implements Runnable {





    /**

     * Main method of the class

     */

    @Override

    public void run() {

        

        // Writes a messsage

        System.out.printf("Begining data sources loading: %s\n",new Date());

        // Sleeps four seconds

        try {

            TimeUnit.SECONDS.sleep(4);

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

        // Writes a message

        System.out.printf("Data sources loading has finished: %s\n",new Date());

    }

}

View Code

　　

　　然后创建一个初始化网络的线程

　　

public class NetworkConnectionsLoader implements Runnable {





    /**

     * Main method of the class

     */

    @Override

    public void run() {

        // Writes a message

        System.out.printf("Begining network connections loading: %s\n",new Date());

        // Sleep six seconds

        try {

            TimeUnit.SECONDS.sleep(6);

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

        // Writes a message

        System.out.printf("Network connections loading has finished: %s\n",new Date());

    }

}

View Code

　　

　　通过TimeUnit.SECONDS.sleep()方法; 进行休眠，

 

　　然后主线程执行，通过join方法，当一个线程对象的join方法被调用时，调用他的线程将会被挂起，知道这个线程来完成这些初始化任务，我们在主线程分别调用两个Thread的join方法，那么主线程会等到两个线程都执行完毕才会执行下去。

　　

public class Main {



    /**

     * Main method of the class. Create and star two initialization tasks

     * and wait for their finish

     * @param args

     */

    public static void main(String[] args) {



        // Creates and starts a DataSourceLoader runnable object

        DataSourcesLoader dsLoader = new DataSourcesLoader();

        Thread thread1 = new Thread(dsLoader,"DataSourceThread");

        thread1.start();



        // Creates and starts a NetworkConnectionsLoader runnable object

        NetworkConnectionsLoader ncLoader = new NetworkConnectionsLoader();

        Thread thread2 = new Thread(ncLoader,"NetworkConnectionLoader");

        thread2.start();



        // Wait for the finalization of the two threads

        try {

            thread1.join();

            thread2.join();

        } catch (InterruptedException e) {

            e.printStackTrace();

        }



        // Waits a message

        System.out.printf("Main: Configuration has been loaded: %s\n",new Date());

    }

}