java-線程池-工具類__jdk

匯總JDK內建的四個常用線程池的用法

package thread.pool;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.ScheduledExecutorService;import java.util.concurrent.TimeUnit;public class ThreadPoolUtil {    static ExecutorService cachedThreadPool;    static ExecutorService fixedThreadPool;    static ScheduledExecutorService scheduledThreadPool;    static ExecutorService singleThreadPool;    static ExecutorService cachedThreadPoolRun(Runnable runnable) {        if (cachedThreadPool == null)            cachedThreadPool = Executors.newCachedThreadPool();        cachedThreadPool.submit(runnable);        return cachedThreadPool;    }    public static ExecutorService fixedThreadPoolRun(Runnable runnable) {        if (fixedThreadPool == null)            fixedThreadPool = Executors.newFixedThreadPool(Runtime.getRuntime()                    .availableProcessors());        fixedThreadPool.submit(runnable);        return fixedThreadPool;    }    public static ExecutorService scheduledThreadPoolRun(Runnable runnable, long delay, TimeUnit unit) {        if (scheduledThreadPool == null)            scheduledThreadPool = Executors.newScheduledThreadPool(Runtime.getRuntime()                    .availableProcessors());        scheduledThreadPool.schedule(runnable, delay, unit);        return scheduledThreadPool;    }    public static ExecutorService singleThreadPoolRun(Runnable runnable) {        if (singleThreadPool == null)            singleThreadPool = Executors.newSingleThreadExecutor();        singleThreadPool.submit(runnable);        return singleThreadPool;    }    public static void main(String[] args) {        final Long startTime = System.currentTimeMillis();        ExecutorService executorService = null;        for (int i = 0; i < 1000000; i++) {//            System.out.println(finalI);            final int finalI = i;            Runnable task = () -> System.out.println(finalI);            executorService = ThreadPoolUtil.fixedThreadPoolRun(task);        }        if (executorService != null) {            executorService.shutdown();        }        while (true) {            if (executorService.isTerminated()) {                System.out.println("所有的子線程都結束了。");                break;            }        }        final Long stopTime = System.currentTimeMillis();        System.out.println("---------------------------");        System.out.println(stopTime - startTime);    }}