创建线程的4中方式

1、继承Thread类
2、实现Runnable接口
3、实现Callable接口
4、通过线程池创建

package com.mock;


import org.junit.jupiter.api.Test;

import java.util.concurrent.*;

public class TestThread {
    /**
     * 继承Thread类
     */
    @Test
    public void test1() {
        new Thread1().start();
    }

    /**
     * 实现Runnable接口
     */
    @Test
    public void test2() {
        new Thread(new Thread2()).start();
    }

    /**
     * 实现Callable接口
     */
    @Test
    public void test3() throws ExecutionException, InterruptedException {
        FutureTask<String> f = new FutureTask<>(new Thread3());
        new Thread(f).start();
        //打印结果
        //get()方法会一直阻塞
        System.out.println(f.get());
    }

    /**
     * 使用线程池
     */
    @Test
    public void test4() {
        ExecutorService executorService = Executors.newFixedThreadPool(2);
        executorService.submit(new Thread2());
        executorService.shutdown();
    }
}

class Thread1 extends Thread {
    @Override
    public void run() {
        System.out.println("方式一");
    }
}

class Thread2 implements Runnable {

    @Override
    public void run() {
        System.out.println("方式二");
    }
}

class Thread3 implements Callable<String> {

    @Override
    public String call() throws Exception {
        System.out.println("方式三");
        return "你好世界";
    }
}