Java線程實現的三種模式

1）Thread:

public class ThreadTest extends Thread {

	public void run(){
		System.out.println(Thread.currentThread()+"say : hello");
	}
	
	public static void main(String[] args){
		new ThreadTest().start();
		new ThreadTest().start();
		new ThreadTest().start();
		new ThreadTest().start();
		new ThreadTest().start();
	}
}

執行結果：

Thread[Thread-2,5,main]say : hello
Thread[Thread-4,5,main]say : hello
Thread[Thread-3,5,main]say : hello
Thread[Thread-0,5,main]say : hello
Thread[Thread-1,5,main]say : hello

2）Runnable：

public class RunnableTest implements Runnable{

	public void run() {
		System.out.println(Thread.currentThread()+"say: hello");
	}
	
	public static void main(String[] args){
		RunnableTest rt = new RunnableTest();
		new Thread(rt,"111").start();
		new Thread(rt,"222").start();
		new Thread(rt,"333").start();
		new Thread(rt).start();
		new Thread(rt).start();
	}
}

執行結果：

Thread[111,5,main]say: hello
Thread[333,5,main]say: hello
Thread[Thread-0,5,main]say: hello
Thread[222,5,main]say: hello
Thread[Thread-1,5,main]say: hello

3）Callable：

public class CallableTest implements Callable<String>{//Callable<V>是泛型，不必定爲String類型

	public String call() throws Exception {
		
		System.out.println(Thread.currentThread()+" say : hello");
		return "返回字符串："+Thread.currentThread().toString();
		
	}
	public static void main(String[] args){
		//Callable和Future一個產生結果，一個拿到結果。
        //Callable接口相似於Runnable，可是Runnable不會返回結果，
		//而Callable能夠返回結果，這個返回值能夠被Future拿到，
		//也就是說，Future能夠拿到異步執行任務的返回值。
		CallableTest ct = new CallableTest();//至關於Callable執行call()內容
		CallableTest ct2 = new CallableTest();
		
		FutureTask<String> ft = new FutureTask<>(ct);//至關於Futrue計算Callable返回的結果
		FutureTask<String> ft2 = new FutureTask<>(ct2);
		
		new Thread(ft,"有返回值得線程").start();
		new Thread(ft2).start();
		
		try {
			//callable的返回值
			System.out.println(ft.get());
			System.out.println(ft2.get());
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

執行結果：

Thread[Thread-0,5,main] say : hello
Thread[有返回值得線程,5,main] say : hello
返回字符串：Thread[有返回值得線程,5,main]
返回字符串：Thread[Thread-0,5,main]