Runable与Callable的区别

Callable的3种启动线程的方式
1、Thread启动
public class CallableImpl implements Callable<String> {
    private String acceptStr;
    public CallableImpl(String acceptStr) {
        this.acceptStr = acceptStr;
    }
    @Override
    public String call() throws Exception {
        // 任务等待1 秒
        Thread.sleep(1000);
        return this.acceptStr + ",hello!";
    }
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        //Callable<String> callable = new CallableImpl("afei");
        CallableImpl impl=new CallableImpl ("afei");
        FutureTask<String> task = new FutureTask<String>(impl);
        long beginTime = System.currentTimeMillis();
        // 创建线程
        new Thread(task).start();
        // 调用get()阻塞主线程，反之，线程不会阻塞
        String result = task.get();//阻塞主线程，直至1s后获取到call()的返回内容
        System.out.println("hello : " + result);//返回:afei,hello!
    }
}
2、ExecutorService 启动
public class CallableImpl implements Callable<String> {
    private String acceptStr;
    public CallableImpl(String acceptStr) {
        this.acceptStr = acceptStr;
    }
    @Override
    public String call() throws Exception {
        // 任务等待1 秒
        Thread.sleep(1000);
        return this.acceptStr + ",hello!";
    }
 public static void main(String[] args) throws ExecutionException, InterruptedException {
        ExecutorService exec = Executors.newCachedThreadPool(); // 创建线程池
        // 向里面扔任务并执行该任务，同时返回一个包含call()方法返回值的Featured对象
        CallableImpl impl=new CallableImpl(“afei");
        Future<String> future=exec.submit(impl); 
        System.out.println(future.get()); //打印线程（任务）执行的结果
        exec.shutdown();// 关闭线程池后不接受新任务,已经在线程池的任务会被执行完
    }
}
3、controler方法中直接返回Callable对象或其派对象
@RestController
public class IAsyncController {
    private Logger logger=LoggerFactory.getLogger(getClass());

    @PostMapping("/async/back")
    public Callable<String> back(){
        logger.info("主线程开始");
        Callable<String> c=new Callable<String>() {
            @Override
            public String call() throws Exception {
                // TODO Auto-generated method stub
                logger.info("副线程开始等待1s...");
                Thread.sleep(1000);
                logger.info("副线程结束等待");
                return "afei";
            }
        };
        logger.info("主线程结束并返回");
        return c;//启动副线程并返回call()的返回值
    }
}

Runnable的3种启动线程的方式：
1、继承Thread类
public class Test extends Thread{
  public void run(){
   //操作临界资源
  }
   public static void main(String[] args){
       Test t=new Test();
       t.start();//启动线程
  } 
}
2、继承Runnable接口
public class Test implements Runnable{
  public void run(){
   //操作临界资源
  }
   public static void main(String[] args){
        Test t=new Test(); 
        Thread thread=new Thread(t); 
        thread.start();//启动线程
  } 
}
3、无名线程
public class Test{
   public static void main(String[] args){
       new Thread(()->{  //启动一个线程
            System.out.pritln("启动一个线程);
        }).start();
  } 
}