到目前为止,我们仅用到两个线程:主线程和一个子线程。然而,你的程序可以创建所需的更多线程。例如,下面的程序创建了三个子线程:
// Create multiple threads. class NewThread implements Runnable { String name; // name of thread Thread t; NewThread(String threadname) { name = threadname; t = new Thread(this, name); System.out.println("New thread: " + t); t.start(); // Start the thread } // This is the entry point for thread. public void run() { try { for(int i = 5; i > 0; i--) { System.out.println(name + ": " + i); Thread.sleep(1000); } } catch (InterruptedException e) { System.out.println(name + "Interrupted"); } System.out.println(name + " exiting."); } } class MultiThreadDemo { public static void main(String args[]) { new NewThread("One"); // start threads new NewThread("Two"); new NewThread("Three"); try { // wait for other threads to end Thread.sleep(10000); } catch (InterruptedException e) { System.out.println("Main thread Interrupted"); } System.out.println("Main thread exiting."); } }
程序输出如下所示:
New thread: Thread[One,5,main]
New thread: Thread[Two,5,main]
New thread: Thread[Three,5,main]
One: 5
Two: 5
Three: 5
One: 4
Two: 4
Three: 4
One: 3
Three: 3
Two: 3
One: 2
Three: 2
Two: 2
One: 1
Three: 1
Two: 1
One exiting.
Two exiting.
Three exiting.
Main thread exiting.如你所见,一旦启动,所有三个子线程共享CPU。注意main()中对sleep(10000)的调用。这使主线程沉睡十秒确保它最后结束。
New thread: Thread[One,5,main]
New thread: Thread[Two,5,main]
New thread: Thread[Three,5,main]
One: 5
Two: 5
Three: 5
One: 4
Two: 4
Three: 4
One: 3
Three: 3
Two: 3
One: 2
Three: 2
Two: 2
One: 1
Three: 1
Two: 1
One exiting.
Two exiting.
Three exiting.
Main thread exiting.如你所见,一旦启动,所有三个子线程共享CPU。注意main()中对sleep(10000)的调用。这使主线程沉睡十秒确保它最后结束。