标签：Thread Executors 并发 线程 scheduledExecutorService new executorService

1.可创建线程池种类

在java.util.concurrent中提供了工具类Executors（调度器）对象来创建线程池，有四种

• CachedThreadPool - 可缓存线程池
  • 无限大、无线程创建线程，有空闲线程利用起来
• FixedThreadPool - 定长线程池
  • 固定线程总数，空闲线程用于执行任务，无空闲线程任务等待
• SingleThreadExecutor - 单线程池
• ScheduledThreadPool - 调度线程池

2.线程池的使用

2.1可缓存线程池

        ExecutorService executorService = Executors.newCachedThreadPool();
        for (int i = 0; i < 1000; i++) {
            final int index = i;
            executorService.execute(new Runnable() {
                @Override
                public void run() {
                    System.out.println(Thread.currentThread().getName()+"--"+index);
                }
            });
        }
        executorService.shutdown();

2.2定长线程池

 

        ExecutorService executorService = Executors.newFixedThreadPool(3);
        for (int i = 0; i < 1000; i++) {
            final int index = i;
            executorService.execute(new Runnable() {
                @Override
                public void run() {
                    System.out.println(Thread.currentThread().getName()+"--"+index);
                }
            });
        }
        //关闭线程池，等待所有任务执行完毕
        executorService.shutdown();
        //不等待线程池中的任务执行完毕，直接关闭线程池，不推荐使用
//        executorService.shutdownNow();

2.3单线程池

        ExecutorService executorService = Executors.newSingleThreadExecutor();
        for (int i = 0; i < 1000; i++) {
            final int index = i;
            executorService.execute(new Runnable() {
                @Override
                public void run() {
                    System.out.println(Thread.currentThread().getName()+"--"+index);
                }
            });
        }
        //关闭线程池，等待所有任务执行完毕
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        executorService.shutdown();

2.4调度线程池

执行单次

        ScheduledExecutorService scheduledExecutorService = Executors.newScheduledThreadPool(5);
        //换执行方法，不在是execute，而是schedule
        scheduledExecutorService.schedule(new Runnable() {
            @Override
            public void run() {
                System.out.println(Thread.currentThread().getName()+"-----"+"延迟3秒执行");
            }
        }, 3,java.util.concurrent.TimeUnit.SECONDS);
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        scheduledExecutorService.shutdown();

 

循环执行

        ScheduledExecutorService scheduledExecutorService = Executors.newScheduledThreadPool(5);
        //换执行方法，不在是execute，而是schedule
        System.out.println("当前时间："+new Date());
        scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                System.out.println(Thread.currentThread().getName()+"-----"+new Date()+"--------"+"延迟1秒执行,每3秒执行一次");
            }
        }, 1,3, TimeUnit.SECONDS);
        //大于1s结束才能执行
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        scheduledExecutorService.shutdown();

 

标签：Thread,Executors,并发,线程,scheduledExecutorService,new,executorService
From： https://www.cnblogs.com/blanset/p/16784068.html