创建线程的三种方法

Java 提供了三种创建线程的方法：

1. 通过实现 Runnable 接口；
2. 通过继承 Thread 类本身；
3. 通过 Callable 和 Future 创建线程。

通过实现 Runnable 接口来创建线程

public class RunnableTest {
    public static void main(String[] args) {
        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println("runnable");
            }
        });
        thread.start();
    }
}

通过继承Thread来创建线程

public class ThreadTest {
    public static void main(String[] args) {
        new ThraedDemo().start();
    }

    private static class ThraedDemo extends Thread {
        @Override
        public void run() {
            super.run();
            System.out.println("extends thread");
        }
    }
}

通过 Callable 和 Future 创建线程

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;

public class CallableThreadTest {
    public static void main(String[] args) {
        FutureTask<Integer> ftt = new FutureTask<>(new CallableThreadDemo());
        new Thread(ftt).start();
        try {
            //获得子线程执行结束后的返回值
            System.out.println(ftt.get());
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
    }

    private static class CallableThreadDemo implements Callable<Integer> {

        @Override
        public Integer call() throws Exception {
            return 1;
        }
    }
}