Java线程实现的三种方式详细解析

public class MyThread extends Thread {
　　public void run() {
　　 System.out.println("MyThread.run()");
　　}
}

MyThread myThread1 = new MyThread();
MyThread myThread2 = new MyThread();
myThread1.start();
myThread2.start();

public class MyThread extends OtherClass implements Runnable {
　　public void run() {
　　 System.out.println("MyThread.run()");
　　}
}

MyThread myThread = new MyThread();
Thread thread = new Thread(myThread);
thread.start();

public void run() {
　　if (target != null) {
　　 target.run();
　　}
}

import java.util.concurrent.*;
import java.util.Date;
import java.util.List;
import java.util.ArrayList;
/**
* 有返回值的线程
*/
@SuppressWarnings("unchecked")
public class Test {
    public static void main(String[] args) throws ExecutionException,
    InterruptedException {
       System.out.println("----程序开始运行----");
       Date date1 = new Date();
       int taskSize = 5;
       // 创建一个线程池
       ExecutorService pool = Executors.newFixedThreadPool(taskSize);
       // 创建多个有返回值的任务
       List<Future> list = new ArrayList<Future>();
       for (int i = 0; i < taskSize; i++) {
            Callable c = new MyCallable(i + " ");
            // 执行任务并获取Future对象
            Future f = pool.submit(c);
            // System.out.println(">>>" + f.get().toString());
            list.add(f);
      }
      // 关闭线程池
      pool.shutdown();
      // 获取所有并发任务的运行结果
      for (Future f : list) {
            // 从Future对象上获取任务的返回值，并输出到控制台
            System.out.println(">>>" + f.get().toString());
      }
      Date date2 = new Date();
      System.out.println("----程序结束运行----，程序运行时间【" + (date2.getTime() - date1.getTime()) + "毫秒】");
    }
}
class MyCallable implements Callable<Object> {
    private String taskNum;
    MyCallable(String taskNum) {
       this.taskNum = taskNum;
    }
    public Object call() throws Exception {
       System.out.println(">>>" + taskNum + "任务启动");
       Date dateTmp1 = new Date();
       Thread.sleep(1000);
       Date dateTmp2 = new Date();
       long time = dateTmp2.getTime() - dateTmp1.getTime();
       System.out.println(">>>" + taskNum + "任务终止");
       return taskNum + "任务返回运行结果,当前任务时间【" + time + "毫秒】";
    }
}