Future Callable 线程池 例1

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；

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 weijun.nie
 *
 */
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 weijun.nie
 *
 */
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";
        }
    }
}