Java多线程三种主要实现方式解析

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

public class T02_HowToCreateThread {
  //1.继承Thread类
  static class MyThread extends Thread{
    @Override
    public void run() {
      System.out.println("MyThread-->");
    }
  }
  //3.实现Runnable接口
  static class MyRun implements Runnable{

    @Override
    public void run() {
      System.out.println("MyRunable-->");
    }
  }
  //4.实现Callable接口
  static class MyCall implements Callable{

    @Override
    public Object call() throws Exception {
      System.out.println("myCallable-->");
      return 1;
    }
  }
  public static void main(String[] args) throws ExecutionException, InterruptedException {
    //1.继承Thread类
    new MyThread().start();
    //2.lambda与继承Thread类类//1.继承Thread类似，最简单
    new Thread(()->{
      System.out.println("lambda-->");
    }).start();
    //3.实现Runnable接口
    new Thread(new MyRun()).start();
    new Thread(new Runnable() {
      @Override
      public void run() {
        System.out.println("simple->Runnable");
      }
    }).start();
    //4.实现Callable接口,并用包装器FutureTask来同时实现Runable、Callable两个接口,可带返回结果
    MyCall mycall = new MyCall();
    FutureTask futureTask = new FutureTask(mycall);
    new Thread(futureTask).start();
    System.out.println(futureTask.get());
  }
}

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.*;

/**
 * 使用ExecutorsService、Callable、Future来实现多个带返回值的线程
 */
public class T02_HowToCreateThread02 {
  static class MyCallable implements Callable{
    private int taskNum;

    public MyCallable(int taskNum){
      this.taskNum = taskNum;
    }
    @Override
    public Object call() throws Exception {
      System.out.println("任务"+taskNum);
      return "MyCallable.call()-->task"+taskNum;
    }
  }
  public static void main(String[] args) throws ExecutionException, InterruptedException {
    int num = 5;
    //创建一个线程池
    ExecutorService pool = Executors.newFixedThreadPool(num);
    List<Future> futureList = new ArrayList<Future>();
    for (int i = 0; i < num; i++){
      MyCallable mc = new MyCallable(i);
      //执行任务，并返回值
      Future future = pool.submit(mc);
      futureList.add(future);
    }
    pool.shutdown();
    for (Future f: futureList){
      System.out.println(f.get());
    }
  }
}