JDK自带的多线程API的简单例子

package cn.sunline.ant.task.concurrent;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class Test {

	public static void main(String[] args) {
		// 执行的服务
		ExecutorService service = Executors.newFixedThreadPool(4);
		CompletionService<Result> completion = new ExecutorCompletionService<Result>(service);//这个东西很关键
		// 每个任务的执行结果
		List<Future<Result>> futures = new ArrayList<Future<Result>>();

		// 开始并发的跑任务
		futures.add(completion.submit(new MyTask(10)));
		futures.add(completion.submit(new MyTask(1)));
		futures.add(completion.submit(new MyTask(5)));

		for (int i = 0; i < 3; i++) {
			try {
				// 这里会阻塞等待任务完成
				Result result = completion.take().get();
				System.out.println(result.msg);
			} catch (Exception e) {
				e.printStackTrace();
			}
		}

		//这里的顺序与任务请求的顺序不一定相同，具体要看每个任务的执行速度
		for (Future<Result> f : futures) {
			try {
				// 这里会阻塞等待任务完成
				Result result = f.get();
				System.out.println(result.msg);
			} catch (Exception e) {
				e.printStackTrace();
			}
		}

	}

	static class Result {
		String msg;
	}

	static class MyTask implements java.util.concurrent.Callable<Result> {
		int id;

		public MyTask(int id) {
			this.id = id;
		}

		@Override
		public Result call() throws Exception {
			Result ret = new Result();
			ret.msg = "处理任务：" + id;
			Thread.sleep(id * 1000);
			return ret;
		}
	}

}