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  • Java并发之ThreadPoolExecutor 线程执行服务

     1 package com.thread.test.thread;
     2 
     3 import java.util.concurrent.ExecutorService;
     4 import java.util.concurrent.LinkedBlockingQueue;
     5 import java.util.concurrent.RejectedExecutionHandler;
     6 import java.util.concurrent.ThreadLocalRandom;
     7 import java.util.concurrent.ThreadPoolExecutor;
     8 import java.util.concurrent.TimeUnit;
     9 
    10 /**
    11  * ThreadPoolExecutor
    12  * 通过线程池执行所提交的任务的ExecutorService,通常由Executors生成
    13  * 执行高并发任务比较高效,因为减少了任务的穿行等待时间,同时很好的管理着执行需求的资源,包括线程,
    14  * 通常,维护者一些基础的任务执行数据,例如已完成任务数量
    15  *
    16  * ThreadPoolExecutor有许多可调正的参数,可以适用于不同的用途,但是通常我们使用
    17  * Executors#newCachedThreadPool 无容量限制,线程自动回收
    18  * Executors#newFixedThreadPool 固定容量线程池
    19  * Executors#newSingleThreadExecutor 单线程
    20  * 等为许多通用场景预置了很多参数,
    21  *
    22  * Hello world!
    23  *
    24  */
    25 public class ThreadPoolFactoryTest
    26 {
    27     public static void main( String[] args )
    28     {
    29         /**
    30          * @ int corePoolSize:线程池中维护的线程数量,生命周期同线程池,除非设置了allowCoreThreadTimeOut
    31          * @ int maximumPoolSize:允许的最大数量
    32          * @ long keepAliveTime:允许的最大存活时间
    33          * @ TimeUnit unit:单位
    34          * @ BlockingQueue<Runnable> workQueue:存储等待执行任务,execute提交的Runnable类型任务
    35          * @ RejectedExecutionHandler handler:线程阻塞,队列已满时执行的操作
    36          */
    37         ExecutorService enew = new ThreadPoolExecutor(5, 20, 0L,
    38                 TimeUnit.SECONDS,
    39                 new LinkedBlockingQueue<Runnable>(),
    40         new RejectedExecutionHandler() {
    41                     public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
    42                         System.out.println("this is the exception execution begin");
    43                         executor.execute(r);
    44                         System.out.println("this is the exception execution end");
    45                     }
    46                 });
    47 
    48         for (int i = 0; i < 100; i++) {
    49             enew.execute(new Runnable() {
    50                 public void run() {
    51                     int l = ThreadLocalRandom.current().nextInt();
    52                     System.out.println("task..." + l + "begin");
    53                     try {
    54                         Thread.sleep(2000);
    55                         System.out.println("task..." + l + "end");
    56                     } catch (InterruptedException e) {
    57                         e.printStackTrace();
    58                     }
    59                 }
    60             });
    61         }
    62         System.out.println("add end...");
    63     }
    64 }

    项目地址:https://github.com/windwant/windwant-demo/tree/master/thread-demo

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  • 原文地址:https://www.cnblogs.com/niejunlei/p/5985494.html
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