Future Callable 线程池 例1

package com.niewj.concurrent;

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;

/**
 * Future和Callable例1
 * @author niewj
 *
 */
public class ES_TPE_Test {

	public static void main(String[] args) throws InterruptedException, ExecutionException {
		ExecutorService executerService = Executors.newSingleThreadExecutor();

		// 主线程要做两件事：1.买书; 2.报名考试
		long start = System.currentTimeMillis();

		// 1. 第一件事：买书
		Future<Book> future = executerService.submit(new BuyBookTask()); // 定义了一个任务：买书，需要一定的时间
		executerService.shutdown();

		// 2. 第一件事：报名考试 报名考试花费10秒
		for (int i = 1; i <= 10; i++) {
			Thread.sleep(1000);
			System.out.println("==== ==== 等报名排队等了[ " + i + " ]天了 ==== ==== ");
		}

		Book book = future.get();
		System.out.println("考试报上名了; 书也买到了： " + book);
		long end = System.currentTimeMillis();
		System.out.println("总耗时秒数： " + (end - start) / 1000);

	}

}

/**
 * 购买书籍任务-需要耗费一定时间：假定买书需要等7天(一秒模拟一天)
 *
 * @author niewj
 *
 */
class BuyBookTask implements Callable<Book> {

	final int restockDays = 7; // 等进货时间

	@Override
	public Book call() throws Exception {
		for (int i = 1; i <= restockDays; i++) {
			Thread.sleep(1000);
			System.out.println("等书等了[ " + i + " ]天了。。。。。。");
		}

		return new Book("稀缺书套装", 120.5);
	}

}

class Book {
	private String name;
	private Double price;

	public Book(String name, Double price) {
		this.name = name;
		this.price = price;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public double getPrice() {
		return price;
	}

	public void setPrice(double price) {
		this.price = price;
	}

	@Override
	public String toString() {
		if (this.name == null && this.price == null) {
			return "没有书！";
		} else {
			return name + " 這本書 " + price + "元錢";
		}
	}
}

概述：

 

    main方法：主线程想做两件事=两个任务：报名考试和买书

    但是用一个Callable任务发起一个线程来做买书的任务-耗时7秒；

    主线程自己完成报名考试的任务-耗时10秒；