多线程（1）——多线程的创建与启动

线程的创建

线程的创建主要要3种方法。
1. 继承Thread类

package cn.zengzehao.thread;

public class FirstThread {
    public static void main(String[] args) throws InterruptedException {
        //创建线程
        MyTaskThread thread = new MyTaskThread();
        //或者这样子创建线程
        //Thread thread = new Thread(new MyTaskThread()); 
        //启动线程
        thread.start();

    }
}

class MyTaskThread extends Thread{
    @Override
    //重写父类的run()方法
    public void run() {
        System.out.println("我是继承Thread的线程");
    }
}

1. 实现Runnable接口

package cn.zengzehao.thread;

public class RunnableTest {
    public static void main(String[] args) {
        //创建线程
        Thread thread = new Thread(new MyThread());


        Thread thread2 = new Thread(new Runnable() {

            @Override
            public void run() {
                System.out.println("我是线程2");
            }
        });
        //启动线程
        thread.start();
        thread2.start();
    }
}
class MyThread implements Runnable{

    //实现Runnable接口的run()方法
    @Override
    public void run() {
        try {
            Thread.sleep(2000);
            System.out.println("我是实现Runnable");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

    }

}

1. 通过Callable和Future创建线程

package cn.zengzehao.thread;

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

public class CallableTest {
    public static void main(String[] args) {
        //使用FutureTask类来包装Callable对象
        FutureTask ft = new FutureTask(new MyTask());
        //启动线程
        new Thread(ft).start();
        try {
            //获取线程返回的值
            Integer sum = ft.get();
            System.out.println("打印返回来的值:"+sum);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
    }
}
class MyTask implements Callable<Integer>{

    //实现Callable的call()方法
    @Override
    public Integer call() throws Exception {
        System.out.println("实现Callable");
        int sum = 0;
        for(int i=0;i<=100;i++){
            sum+=i;
        }
        return sum;
    }

}