单例线程池（newSingleThreadExecutor）

单例线程池（newSingleThreadExecutor）

package com.zhw.learning.thread;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * @author zhw
 * 创建一个单线程化的线程池，它只会用唯一的工作线程来执行任务，
 * 保证所有任务按照指定顺序(FIFO, LIFO, 优先级)执行
 *
 * Executors.newSingleThreadExecutor():
 * public static ExecutorService newSingleThreadExecutor() {
 *         return new FinalizableDelegatedExecutorService
 *             (new ThreadPoolExecutor(1, 1,
 *                                     0L, TimeUnit.MILLISECONDS,
 *                                     new LinkedBlockingQueue<Runnable>()));
 *     }
 */
public class SingleThreadExecutorTest {

    public static void main(String[] args) {
        ExecutorService singleThreadExecutor = Executors.newSingleThreadExecutor();

        for (int i = 0; i < 5; i++) {
            final int index = i;
            singleThreadExecutor.execute(new Runnable() {
                @Override
                public void run() {
                    try {
                        SimpleDateFormat sdf = new SimpleDateFormat(
                                "HH:mm:ss");
                        System.out.println("运行时间: " +
                                sdf.format(new Date()) + " " + index);
                        Thread.sleep(2000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            });
        }

        singleThreadExecutor.shutdown();
    }
}

该线程池类似于单线程执行，所以先执行完前一个任务后，再顺序执行下一个任务，
运行结果如下：