线程池ThreadPoolExecutor
1-ThreadPool线程池
1.1 为什么要用线程池
1.2 线程池的架构--ThreadPoolExecutor
1.3 线程池的构造方法
package thread20200415;import java.util.concurrent.Executor;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.TimeUnit;/** * 线程池：ThreadPoolExecutor * @author zhaomin * @date 2020/4/15 23:39 */public class ThreadPoolTest { public static void main(String[] args) { //一池多线程 //ExecutorService threadPool= Executors.newFixedThreadPool(5); //一池一线程 // ExecutorService threadPool= Executors.newSingleThreadExecutor(); //一池N线程 ExecutorService threadPool= Executors.newCachedThreadPool(); for(int i=0;i<10;i++) { threadPool.execute(()->{ System.out.println(Thread.currentThread().getName()+'办理业务'); }); try { TimeUnit.SECONDS.sleep(1); } catch (InterruptedException e) { e.printStackTrace(); } } threadPool.shutdown(); }}1.4线程池中的几个重要参数
1.5线程池底层工作原理
9.6 ***的、单一的、可扩容的用哪一种？
一个都不用
1.7 拒绝策略
package thread20200415;import java.util.concurrent.*;/** * 线程池：ThreadPoolExecutor * @author zhaomin * @date 2020/4/15 23:39 */public class ThreadPoolTest { public static void main(String[] args) { //一池多线程 //ExecutorService threadPool= Executors.newFixedThreadPool(5); //一池一线程 // ExecutorService threadPool= Executors.newSingleThreadExecutor(); //一池N线程// ExecutorService threadPool= Executors.newCachedThreadPool(); /*在实际开发中，要用自定义的线程池 * ThreadPoolExecutor.AbortPolicy()---会报异常 * ThreadPoolExecutor.CallerRunsPolicy()--多余的任务返回给调用者线程来执行 * ThreadPoolExecutor.DiscardPolicy()--直接拒绝，默默工作--最好了 * ThreadPoolExecutor.DiscardOldestPolicy()--踢掉最早来到阻塞队列等待的任务，给新任务腾地方*//**public ThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler) {*/ ExecutorService threadPool= new ThreadPoolExecutor( 2, 3, 2L, TimeUnit.SECONDS, new LinkedBlockingQueue(3), Executors.defaultThreadFactory(), new ThreadPoolExecutor.DiscardOldestPolicy()); try { for (int i = 0; i < 10; i++) { threadPool.execute(() -> { System.out.println(Thread.currentThread().getName() + '办理业务'); }); } } catch (Exception e) { e.printStackTrace(); }finally{ threadPool.shutdown(); } }}