文章目录 在第一部分中介绍完java中Executors的线程池创建的方式之后,实际上有一个非常好奇的问题。...既然newFixedThreadPool(1)也能保证创建只有一个线程运行的线程池,那么为什么还需要一个newSingleThreadExecutor()方法呢?带着这个问题我们来详细分析。...: java.util.concurrent.Executors$FinalizableDelegatedExecutorService cannot be cast to java.util.concurrent.ThreadPoolExecutor...at com.dhb.threadpool.DifferentTest.main(DifferentTest.java:17) 也就是说,二者的最大区别在于,newFixedThreadPool(1...分析了newFixedThreadPool(1)和newSingleThreadExecutor()的区别。实际上这两种设计是有原因的。而且对于后者这种将核心功能隔隔离的设计模式,非常值得我们借鉴。
文章目录 前言 一、线程池示例 二、newCachedThreadPool 线程池示例 三、newFixedThreadPool 线程池示例 三、newSingleThreadExecutor 线程池示例...; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; public class Main...e.printStackTrace(); } } } } 执行结果 : 该线程池中创建了 100 个线程 , 执行 100 个任务 ; 三、newFixedThreadPool...线程池示例 ---- import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; public...public static void main(String[] args) { ExecutorService executorService2 = Executors.newFixedThreadPool
触发报警的代码大概如下: boolean start=true; public void doSomeThing(){ ExecutorService executorService = Executors.newFixedThreadPool...上面的代码存在两个问题: start是个主线程的变量,在主线程修改值,子线程的while循环不会停止 上述代码能够停止,因为在内部调用`Thread.sleep方法,导致线程内的变量刷新 newFixedThreadPool...ExecutorService executorService; Thread thread ; public void doSomeThing(){ executorService = Executors.newFixedThreadPool
看这块代码的问题:咋一看,好像没什么问题,但深入分析,问题就出现在 Executors.newFixedThreadPool(15)这段代码上。...最终抛出内存异常 Exception in thread "pool-1-thread-295" java.lang.OutOfMemoryError: Java heap space 然而,电脑本机的实体内存...Java提供的四种常用线程池解析 Executors 既然楼主踩坑就是使用了 JDK 的默认实现,那么再来看看这些默认实现到底干了什么,封装了哪些参数。...newFixedThreadPool public static ExecutorService newFixedThreadPool(int nThreads) { return new...LinkedBlockingQueue())); } 注意:该静态方法,禁止使用,因为里面有不少坑,这里不做过多解释 关于线程池的阻塞队列的各种用法,请参见博文: 【小家java
面试官经常会问这个问题,本文将基于源码,去分析newFixedThreadPool线程池导致的内存飙升问题,希望能加深大家的理解。...线程池源码分析 以上的实例代码,就一个newFixedThreadPool和一个execute方法。...首先,我们先来看一下newFixedThreadPool方法的源码 newFixedThreadPool源码 public static ExecutorService newFixedThreadPool...空闲时间为0,即keepAliveTime为0 阻塞队列为无参构造的LinkedBlockingQueue 线程池特点了解不是很清楚的朋友,可以看我这篇文章,面试必备:Java线程池解析 接下来,我们再来看看线程池执行方法...参考与感谢 《Java并发编程之美》 面试必备:Java线程池解析
); 从线程池中获取一个线程对象,并且执行给定的Runnable接口实现类对象作为执行目标 代码如下: package executors; import java.util.concurrent.ExecutorService...; import java.util.concurrent.Executors; class Thread1 implements Runnable{ @Override public void...= Executors.newFixedThreadPool(5); Thread1 thread1 = new Thread1(); newFixedThreadPool.submit...(thread1); newFixedThreadPool.submit(thread1); newFixedThreadPool.submit(thread1); newFixedThreadPool.submit...newFixedThreadPool.submit(thread1); newFixedThreadPool.submit(thread1); newFixedThreadPool.submit
——怀特 对应的单元测试: import org.junit.jupiter.api.Test; import java.util.concurrent.ExecutorService; import...java.util.concurrent.Executors; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicReference...AtomicReference("initial"); int numberOfThreads = 10; ExecutorService executor = Executors.newFixedThreadPool...AtomicReference(0); int numberOfThreads = 10; ExecutorService executor = Executors.newFixedThreadPool...AtomicReference(0); int numberOfThreads = 10; ExecutorService executor = Executors.newFixedThreadPool
其常用方法有newFixedThreadPool、newSingleThreadExecutor、newCachedThreadPool等。...2.1 newFixedThreadPool public static ExecutorService newFixedThreadPool(int nThreads) Creates a thread...与newFixedThreadPool(1)不同,返回的Executor保证不会重新配置以使用其他的线程。...我们可以看看这些方法的源代码: 4.1 newFixedThreadPool public static ExecutorService newFixedThreadPool(int nThreads...newFixedThreadPool和newSingleThreadExecutor使用的是无界队列LinkedBlockingQueue。
package executors; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors...; public class Demo2 { public static void main(String[] args) { ExecutorService newFixedThreadPool...= Executors.newFixedThreadPool(5); newFixedThreadPool.submit(new Runnable() { @Override...package com.qfedu.c_lambda; import java.util.Arrays; import java.util.Comparator; public class Demo2...数据类型真的可以省略,虽然是不同数据类型,Java语言真香 * 2.
--------newFixedThreadPool (创建一个定长线程池,可控制线程最大并发数,超出的线程会在队列中等待。)...public static ExecutorService newFixedThreadPool(int nThreads); public static ExecutorService newFixedThreadPool...import android.util.Log; 7 import android.view.Menu; 8 import android.view.MenuItem; 9 10 import java.util.concurrent.CyclicBarrier...; 11 import java.util.concurrent.ExecutorService; 12 import java.util.concurrent.Executors; 13 import...java.util.concurrent.ThreadFactory; 14 15 16 public class MyActivity extends Activity { 17 18
创建线程池的方法 一、创建线程池的三种方法 Executors.newSingleThreadExecutor(); //单个线程 Executors.newFixedThreadPool(5); /...}catch (Exception e) { e.printStackTrace(); }finally { //关闭线程池 threadPool.shutdown(); } } } 2. newFixedThreadPool...import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; public class ExecuterTest1...{ public static void main(String[] args) { ExecutorService threadPool = Executors.newFixedThreadPool...)); } //############################################################# public static ExecutorService newFixedThreadPool
Executors Executors 是一个Java中的工具类。提供工厂方法来创建不同类型的线程池。...常用方法有以下几个: //创建固定数目线程的线程池 ExecutorService executor1 = Executors.newFixedThreadPool(8); //创建一个可缓存的线程池,...private static ExecutorService executor = Executors.newFixedThreadPool(8); public static void main...: GC overhead limit exceeded at java.util.concurrent.LinkedBlockingQueue.offer(LinkedBlockingQueue.java...而newFixedThreadPool中创建LinkedBlockingQueue时,并未指定容量。
二、线程池的关键类的关系图 从上面可以看出Java的线程池主的实现类主要有两个类ThreadPoolExecutor和ForkJoinPool。...()——创建一个单线程的线程池 2、newFixedThreadPool(int n)——创建一个固定大小的线程池 3、newCachedThreadPool()——创建一个可缓存的线程池 4、newScheduledThreadPool...()固定线程数的线程池 public static ExecutorService newFixedThreadPool(int nThreads) { return new ThreadPoolExecutor...; } } ThreadPoolTest.java ThreadPoolTest.java import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors...import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; public class ThreadPoolTest
--------newFixedThreadPool (创建一个定长线程池,可控制线程最大并发数,超出的线程会在队列中等待。)...public static ExecutorService newFixedThreadPool (int nThreads); public static ExecutorService newFixedThreadPool...import android.util.Log; 7 import android.view.Menu; 8 import android.view.MenuItem; 9 10 import java.util.concurrent.CyclicBarrier...; 11 import java.util.concurrent.ExecutorService; 12 import java.util.concurrent.Executors; 13 import...java.util.concurrent.ThreadFactory; 14 15 16 public class MyActivity extends Activity { 17 18
目录 线程池背景知识 创建线程池 ExecutorService的使用 线程池背景知识 涉及到的是java.util.concurrent包中的ExecutorService。...ExecutorService就是Java中对线程池的实现。 Java API对ExecutorService接口的实现有两个,所以这两个即是Java线程池具体实现类 1....2. newFixedThreadPool 创建一个定长线程池,可控制线程最大并发数,超出的线程会在队列中等待。...ExecutorService的使用 ExecutorService executorService = Executors.newFixedThreadPool(10); executorService.execute...线程池 ExecutorService cacheExecutor = Executors.newFixedThreadPool(100); if(userxx !
之所以这么说,是因为这种创建线程池的方式有很大的隐患,稍有不慎就有可能导致线上故障,如:【小家Java】一次Java线程池误用(newFixedThreadPool)引发的线上血案和总结 本文我们就来围绕这个问题来分析一下为什么...此类看起来功能还是比较强大的,又用到了工厂模式、又有比较强的扩展性,重要的是用起来还比较方便,如: ExecutorService executor = Executors.newFixedThreadPool...大家也可以完全的遵守一下吧 简单例子模拟一下OOM public class ExecutorsDemo { private static ExecutorService executor = Executors.newFixedThreadPool...实现的: public static ExecutorService newFixedThreadPool(int nThreads) { return new ThreadPoolExecutor...因此是个无界队列 上面提到的问题主要体现在newFixedThreadPool和newSingleThreadExecutor两个工厂方法上,并不是说newCachedThreadPool和newScheduledThreadPool
使用方式: import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; public class...2.newFixedThreadPool 创建方式: ExecutorService pool = Executors.newFixedThreadPool(10); 创建固定大小的线程池。...newFixedThreadPool:一个固定大小的线程池,可以用于已知并发压力的情况下,对线程数做限制。...(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java...(ThreadPoolExecutor.java:823) at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java
Java 四种线程池的用法分析 1、new Thread的弊端 执行一个异步任务你还只是如下new Thread吗?...2、Java 线程池 Java通过Executors提供四种线程池,分别为: newCachedThreadPool创建一个可缓存线程池,如果线程池长度超过处理需要,可灵活回收空闲线程,若无可回收,则新建线程...实例代码 一、固定大小的线程池,newFixedThreadPool: package app.executors; import java.util.concurrent.Executors;...import java.util.concurrent.ExecutorService; /** * Java线程:线程池 * * @author xiho */ public...改变ExecutorService pool = Executors.newFixedThreadPool(5)中的参数:ExecutorService pool = Executors.newFixedThreadPool
线程池不允许使用 Executors 去创建的原因 ---- java.util.concurrent.Executors#newFixedThreadPool(...)解析 public static...ExecutorService newFixedThreadPool(int nThreads) { return new ThreadPoolExecutor(nThreads, nThreads...new LinkedBlockingQueue()); } public static ExecutorService newFixedThreadPool...java.util.concurrent.Executors#newSingleThreadExecutor(...)...jdk源码版本: java version "17.0.2" 2022-01-18 LTS Java(TM) SE Runtime Environment (build 17.0.2+8-LTS-86)
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