兩種方法判斷線程池停止？

一、 ExecutorService 自身方法

1. void shutdown;會拒絕繼續提交任務到隊列，但會把正在執行的任務和隊列中的任務執行完。
2. boolean isShutdown;判斷是否開始了關閉工作，爲ture不代表線程池已經關閉，只代表可以執行關閉任務了。
3. boolean isTerminated;代表線程已經真正終結了。
4. boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException; 等待一點時間，如果線程池終結返回true，沒有終結返回false，如果線程被打斷拋異常。
5. List shutdownNow;立刻發送中斷信號，終止所有線程，並返回一個停止線程的隊列，要求線程能夠正確響應中斷。
6. 使用 threadPoll.shutdown()和 threadPoll.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);配合

package com.example.thread.threadlocal.scene1;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * 加 ThreadLocal 解決
 * 關閉線程池方法 {@link ExecutorService awaitTermination}
 * @author xuyy
 */
public class ThreadLocalDemo08 {

    public static ExecutorService threadPoll = new ThreadPoolExecutor(16, 16,
            0L, TimeUnit.MILLISECONDS,
            new ArrayBlockingQueue<>(1000));

    public SimpleDateFormat simpleDateFormat = new SimpleDateFormat("mm:ss");


    public static void main(String[] args) throws InterruptedException {
        long st = System.currentTimeMillis();
        for (int i = 0; i < 1000; i++) {
            int finalI = i;
            threadPoll.execute(() -> {
                String date = date(finalI);
                System.out.println(date);
            });
        }
        threadPoll.shutdown();
        threadPoll.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
        if (threadPoll.isTerminated()) {
            long et = System.currentTimeMillis();
            System.out.println("耗時：" + (et - st) + "秒");
        }
    }


    public static String date(int seconds) {
        Date date = new Date(1000 * seconds);
        SimpleDateFormat simpleDateFormat = ThreadSafeFormat.dataFormatterThreadLocal.get();
        System.out.println(System.identityHashCode(simpleDateFormat));
        return simpleDateFormat.format(date);
    }

    static class ThreadSafeFormatter06 {
        public static ThreadLocal<SimpleDateFormat> simpleDateFormatThreadLocal = new ThreadLocal<SimpleDateFormat>() {
            @Override
            protected SimpleDateFormat initialValue() {
                return new ThreadLocalDemo08().simpleDateFormat;
            }

        };
    }
}

二、CountDownLatch類

2. 使用CountDownLatch

package com.example.thread.threadlocal.scene1;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * 加 ThreadLocal 解決
 * <p>
 * {@link ThreadLocal} 用作保存每個線程獨享的對象，爲每個線程都創建一個副本，每個線程都只能修改自己所擁有的副本,
 * 而不會影響其他線程的副本，這樣就讓原本在併發情況下，線程不安全的情況變成了線程安全的情況。
 * * 關閉線程池方法 {@link CountDownLatch await}
 *
 * @author xuyy
 */
public class ThreadLocalDemo06 {

    public static ExecutorService threadPoll = new ThreadPoolExecutor(16, 16,
            0L, TimeUnit.MILLISECONDS,
            new ArrayBlockingQueue<>(1000));

    public SimpleDateFormat simpleDateFormat = new SimpleDateFormat("mm:ss");


    public static void main(String[] args) throws InterruptedException {
        long st = System.currentTimeMillis();
        CountDownLatch countDownLatch = new CountDownLatch(1000);
        for (int i = 0; i < 1000; i++) {
            int finalI = i;
            threadPoll.execute(() -> {
                String date = date(finalI);
                System.out.println(date);
                countDownLatch.countDown();
            });
        }
        countDownLatch.await();
        long et = System.currentTimeMillis();
        System.out.println("耗時："+(et-st)+"秒");
    }


    public static String date(int seconds) {
        Date date = new Date(1000 * seconds);
        SimpleDateFormat simpleDateFormat = ThreadSafeFormat.dataFormatterThreadLocal.get();
        System.out.println(System.identityHashCode(simpleDateFormat));
        return simpleDateFormat.format(date);
    }

    static class ThreadSafeFormatter06 {
        public static ThreadLocal<SimpleDateFormat> simpleDateFormatThreadLocal = new ThreadLocal<SimpleDateFormat>() {
            @Override
            protected SimpleDateFormat initialValue() {
                return new ThreadLocalDemo06().simpleDateFormat;
            }

        };
    }
}