多线程_04_了解Callable_jvc编程-优快云博客

本文介绍Java中实现多线程的第三种方式：通过实现Callable接口并重写call方法。示例展示了如何使用Callable创建线程，通过ExecutorService提交任务，并获取Future结果。同时，提供了具体的代码案例，包括图片下载和龟兔赛跑模拟。

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创建多线程的第三种方式：实现Callable,重写call方法
在这里只是了解，因为不属于我这初级菜鸟要掌握的任务，这个内容属于高级并发编程jvc编程。
在这里插入图片描述
案例

package com.cb.thread;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

/*
 * 创建线程方式三
 * 实现callable + 重写call
 * 
 * 
 * 推荐：避免单继承的局限性，优先使用接口
 */
public class CDownloader implements Callable<Boolean> {
	private String url; 	//图片地址
	private String name; //存储名字
	
	public CDownloader(String url,String name) {
		this.url = url;
		this.name = name;

	}
	public Boolean call() throws Exception{
		WebDownloader wd = new WebDownloader();
		wd.downloader(url, name);
		return true;
	}
	public static void main(String[] args) throws InterruptedException, ExecutionException {
		CDownloader cd1 = new CDownloader("http://pic1.win4000.com/wallpaper/c/579f1942850a7.jpg", "杨洋");
		CDownloader cd2 = new CDownloader("http://file06.16sucai.com/2016/0420/faa06f4f0566466e800885110a56cc32.jpg", "婴儿");
		CDownloader cd3 = new CDownloader("https://pic.sogou.com/pics/recompic/detail.jsp?category=%E6%98%8E%E6%98%9F&tag=%E5%90%B4%E4%BA%A6%E5%87%A1#33%2617313718", "吴亦凡");
		
		//创建执行服务
		ExecutorService ser = Executors.newFixedThreadPool(3);
		//提交执行
		Future<Boolean> result1 = ser.submit(cd1);
		Future<Boolean> result2 = ser.submit(cd2);
		Future<Boolean> result3 = ser.submit(cd3);
		//获取结果
		boolean r1 = result1.get();
		boolean r2 = result2.get();
		boolean r3 = result3.get();
		//关闭服务
		ser.shutdownNow();

	}
	
}

把龟免赛跑的案例改成第三种方法，实现Callable接口+重写call方法

package com.cb.thread;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

/*
 * 模拟龟兔赛跑
 */

public class CRacer implements Callable<Integer>{
	private String winner; //胜利者
	@Override
	public Integer call() throws Exception {
		for (int steps=0;steps<=100;steps++) {
			//模拟兔子休息
			if (Thread.currentThread().getName().equals("pool-1-thread-1")&& steps%60==0) {//兔子每走60步休息一次
				try {
					Thread.sleep(100);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			System.out.println(Thread.currentThread().getName()+"-->"+steps);
			//把步数传过去，看比赛是否结束 
			boolean flag = gameOver(steps);
			if(flag){
				return steps;
			}
		}
		
		return null;
		
	}
	private boolean gameOver(int steps){
		if (winner!=null) {//存在胜利者
			return true;
		}else {
			if (steps==100) {
				winner = Thread.currentThread().getName();
				System.out.println("胜利者:"+winner);
				
				return true;
			}
		}
		return false;
	}
	public static void main(String[] args) throws InterruptedException, ExecutionException {
		CRacer racer = new CRacer();
		//创建执行服务
		ExecutorService ser = Executors.newFixedThreadPool(2);
		//提交执行
		Future<Integer> result1 = ser.submit(racer);
		Future<Integer> result2 = ser.submit(racer);
		//获取结果
		Integer r1 = result1.get();
		Integer r2 = result2.get();
		System.out.println(r1 +"-->"+r2);
		//关闭服务
		ser.shutdownNow();
		
	}
	
}