Java 利用 JUC CountDownLatch 线程池 Executors 实现多线程操作

import org.springframework.util.CollectionUtils;
import java.util.List;import java.util.concurrent.CountDownLatch;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.TimeUnit;import java.util.function.Consumer;import java.util.stream.Collectors;import java.util.stream.Stream;
/** * 多线程任务处理工具类 * gzh-JavaNice */public class TaskDisposeUtils {    //并行线程数    public static final int POOL_SIZE;    static {        //判断核心线程数 如果机器的核心线程数大于5则用机器核心线程数        POOL_SIZE = Integer.max(Runtime.getRuntime().availableProcessors(), 5);    }    /**     * 并行处理，并等待结束     *     * @param taskList 任务列表     * @param consumer 消费者     * @param <T>     * @throws InterruptedException     */    public static <T> void dispose(List<T> taskList, Consumer<T> consumer) throws InterruptedException {        dispose(true, POOL_SIZE, taskList, consumer);    }    /**     * 并行处理，并等待结束     *     * @param moreThread 是否多线程执行     * @param poolSize   线程池大小     * @param taskList   任务列表     * @param consumer   消费者     * @param <T>     * @throws InterruptedException     */    public static <T> void dispose(boolean moreThread, int poolSize, List<T> taskList, Consumer<T> consumer) throws InterruptedException {        if (CollectionUtils.isEmpty(taskList)) {            return;        }        //如果是多线程且核心线程数大于一则进入方法        if (moreThread && poolSize > 1) {            poolSize = Math.min(poolSize, taskList.size());            ExecutorService executorService = null;            try {                //新建一个固定大小的线程池 核心线程数为poolSize                executorService = Executors.newFixedThreadPool(poolSize);                //juc工具类 用于让必须所有任务都处理完后才进行下一步                CountDownLatch countDownLatch = new CountDownLatch(taskList.size());                for (T item : taskList) {                    executorService.execute(() -> {                        try {                            //消费任务                            consumer.accept(item);                        } finally {                            //处理完后减一                            countDownLatch.countDown();                        }                    });                }                //在此等待 当countDownLatch变成0后才继续进行下一步                countDownLatch.await();            } finally {                if (executorService != null) {                    executorService.shutdown();                }            }        } else {            for (T item : taskList) {                consumer.accept(item);            }        }    }   public static void main(String[] args) throws InterruptedException {        //生成1-10的10个数字，放在list中，相当于10个任务        List<Integer> list = Stream.iterate(1, a -> a + 1).limit(10).collect(Collectors.toList());        JSONObject object=new JSONObject();        object.put("name","sss");        //启动多线程处理list中的数据，每个任务休眠时间为list中的数值//        Consumer<Integer> c= item -> {//            try {//                long startTime = System.currentTimeMillis();//                object.put("s",item);//                TimeUnit.SECONDS.sleep(item);//                long endTime = System.currentTimeMillis();//                System.out.println(object.toJSONString());//                System.out.println(System.currentTimeMillis() + ",任务" + item + "执行完毕，耗时:" + (endTime - startTime));//            } catch (InterruptedException e) {//                e.printStackTrace();//            }//        };        TaskDisposeUtils.dispose(list, item -> {            try {                long startTime = System.currentTimeMillis();                object.put("s",item);                TimeUnit.SECONDS.sleep(item);                long endTime = System.currentTimeMillis();                System.out.println(object.toJSONString());                System.out.println(System.currentTimeMillis() + ",任务" + item + "执行完毕，耗时:" + (endTime - startTime));            } catch (InterruptedException e) {                e.printStackTrace();            }        });        //上面所有任务处理完毕完毕之后，程序才能继续        System.out.println(list + "中的任务都处理完毕!");    }}