java.util.concurrent.ExecutorService接口提供了许多线程管理的方法

Method 说明
shutdown 拒绝接收新的任务，待已提交的任务执行后关闭，且宿主线程不阻塞，若需要阻塞可借助awaitTermination实现
shutdownNow 停止所有正在执行的任务，挂起未执行的任务并关闭，且宿主线程不阻塞，若需要阻塞可借助awaitTermination实现
awaitTermination 当发生shutdown时，阻塞宿主线程直到约定的时间已过或者所有任务完成
submit 提交任务Callable/Runnable，可利用Future的get()方法使宿主线程阻塞直到任务结束后返回结果

有了以上方法，便可以基于此接口实现线程池的各种功能(例如java.util.concurrent.ThreadPoolExecutor/java.util.concurrent.ScheduledThreadPoolExecutor)，以java.util.concurrent.ThreadPoolExecutor为例，其参数的详解

Name Type 说明
corePoolSize int 线程池中最小的线程数
maximumPoolSize int 线程池中最大的线程数
keepAliveTime long 线程空闲时间，若线程数大于corePoolSize，空闲时间超过该值的线程将被终止回收
unit TimeUnit keepAliveTime的时间单位
workQueue BlockingQueue<Runnable> 已提交但未执行的任务队列
threadFactory ThreadFactory 创建新线程的工厂
handler RejectedExecutionHandler 当线程池或队列达到上限拒绝新任务抛出异常时的处理类

同时，java.util.concurrent.Executors类提供的常用方法有

Method 说明 基类
newFixedThreadPool 线程池中含固定数量的线程 基于java.util.concurrent.ThreadPoolExecutor类
newSingleThreadExecutor 线程池中仅含一个工作线程
newCachedThreadPool 按需创建线程，若线程池中无可用线程，则创建新的线程并加入，直到线程数达到上限值(Integer.MAX_VALUE)
newWorkStealingPool 按照可用CPU数创建线程池 基于java.util.concurrent.ForkJoinPool类

java.util.concurrent.ForkJoinPool类是Fork/Join框架的实现类，Fork/Join框架是Java7提供了的一个用于并行执行任务的框架， 是一个把大任务分割成若干个小任务，最终汇总每个小任务结果后得到大任务结果的框架，该类在有递归实现的场景有更优异的表现。

测试代码如下

import java.util.Date;

import java.util.concurrent.Callable;

import java.util.concurrent.ExecutionException;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Future;

import java.util.concurrent.TimeUnit;

import org.junit.Assert;

import org.junit.Test;

/**

 * @Description: 测试ExecutorService

 */

public class ThreadExecutorServiceTest {

    private static final String THIS_IS_SHUTDOWN_WITH_AWAIT_TERMINATION = "This is shutdownWithAwaitTermination";

    private static final int RESULT = 111;

    private static boolean submitRunnable() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newSingleThreadExecutor();

        Future<?> future = executorService.submit(new Runnable() {

            @Override

            public void run() {

                System.out.println("This is submitRunnable");

            }

        });

        return future.get() == null;

    }

    private static Integer submitRunnableWithResult() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newSingleThreadExecutor();

        Future<Integer> future = executorService.submit(new Runnable() {

            @Override

            public void run() {

                System.out.println("This is submitRunnableWithResult");

            }

        }, RESULT);

        return future.get();

    }

    private static Integer submitBlockCallable() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newFixedThreadPool(1);

        Future<Integer> future = executorService.submit(new Callable<Integer>() {

            @Override

            public Integer call() throws Exception {

                System.out.println("This is submitBlockCallable");

                return RESULT;

            }

        });

        return future.get();// 阻塞

    }

    private static boolean submitNonBlockCallable() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newFixedThreadPool(1);

        Future<Integer> future = executorService.submit(new Callable<Integer>() {

            @Override

            public Integer call() throws Exception {

                System.out.println("This is submitNonBlockCallable");

                return RESULT;

            }

        });

        while (!future.isDone()) {// 非阻塞

            System.out.println(new Date());

        }

        return future.isDone();

    }

    private static String shutdown() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newFixedThreadPool(1);

        final StringBuilder sb = new StringBuilder();

        executorService.submit(new Callable<Integer>() {

            @Override

            public Integer call() throws Exception {

                Thread.sleep(10000);

                sb.append("This is shutdown");

                return RESULT;

            }

        });

        executorService.shutdown();

        return sb.toString();

    }

    private static String shutdownWithAwaitTermination() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newFixedThreadPool(1);

        final StringBuilder sb = new StringBuilder();

        executorService.submit(new Callable<Integer>() {

            @Override

            public Integer call() throws Exception {

                Thread.sleep(10000);

                sb.append(THIS_IS_SHUTDOWN_WITH_AWAIT_TERMINATION);

                return RESULT;

            }

        });

        executorService.shutdown();

        executorService.awaitTermination(Integer.MAX_VALUE, TimeUnit.DAYS);

        return sb.toString();

    }

    @Test

    public void test() throws InterruptedException, ExecutionException {

        Assert.assertTrue(submitRunnable());

        Assert.assertEquals(RESULT, submitRunnableWithResult().intValue());

        Assert.assertEquals(RESULT, submitBlockCallable().intValue());

        Assert.assertTrue(submitNonBlockCallable());

        Assert.assertTrue(shutdown().isEmpty());

        Assert.assertEquals(THIS_IS_SHUTDOWN_WITH_AWAIT_TERMINATION, shutdownWithAwaitTermination());

    }

}

---恢复内容结束---

java.util.concurrent.ExecutorService接口提供了许多线程管理的方法

Method 说明
shutdown 拒绝接收新的任务，待已提交的任务执行后关闭，且宿主线程不阻塞，若需要阻塞可借助awaitTermination实现
shutdownNow 停止所有正在执行的任务，挂起未执行的任务并关闭，且宿主线程不阻塞，若需要阻塞可借助awaitTermination实现
awaitTermination 当发生shutdown时，阻塞宿主线程直到约定的时间已过或者所有任务完成
submit 提交任务Callable/Runnable，可利用Future的get()方法使宿主线程阻塞直到任务结束后返回结果

有了以上方法，便可以基于此接口实现线程池的各种功能(例如java.util.concurrent.ThreadPoolExecutor/java.util.concurrent.ScheduledThreadPoolExecutor)，以java.util.concurrent.ThreadPoolExecutor为例，其参数的详解

Name Type 说明
corePoolSize int 线程池中最小的线程数
maximumPoolSize int 线程池中最大的线程数
keepAliveTime long 线程空闲时间，若线程数大于corePoolSize，空闲时间超过该值的线程将被终止回收
unit TimeUnit keepAliveTime的时间单位
workQueue BlockingQueue<Runnable> 已提交但未执行的任务队列
threadFactory ThreadFactory 创建新线程的工厂
handler RejectedExecutionHandler 当线程池或队列达到上限拒绝新任务抛出异常时的处理类

同时，java.util.concurrent.Executors类提供了基于java.util.concurrent.ThreadPoolExecutor类的工具方法，常用方法有

Method 说明
newFixedThreadPool 线程池中含固定数量的线程
newSingleThreadExecutor 线程池中仅含一个工作线程
newCachedThreadPool 按需创建线程，若线程池中无可用线程，则创建新的线程并加入，直到线程数达到上限值(Integer.MAX_VALUE)

测试代码如下

import java.util.Arrays;

import java.util.Date;

import java.util.List;

import java.util.concurrent.Callable;

import java.util.concurrent.ExecutionException;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.ForkJoinPool;

import java.util.concurrent.Future;

import java.util.concurrent.TimeUnit;

import org.junit.Assert;

import org.junit.Test;

import org.lxp.multiple.thread.task.SumTask;

/**

 * @Description: 测试ExecutorService

 * @author Super.Li

 * @date Jul 6, 2017

 */

public class ThreadExecutorServiceTest {

    private static final String THIS_IS_SHUTDOWN_WITH_AWAIT_TERMINATION = "This is shutdownWithAwaitTermination";

    private static final int RESULT = 111;

    private static boolean submitRunnable() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newSingleThreadExecutor();

        Future<?> future = executorService.submit(new Runnable() {

            @Override

            public void run() {

                System.out.println("This is submitRunnable");

            }

        });

        return future.get() == null;

    }

    private static Integer submitRunnableWithResult() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newSingleThreadExecutor();

        Future<Integer> future = executorService.submit(new Runnable() {

            @Override

            public void run() {

                System.out.println("This is submitRunnableWithResult");

            }

        }, RESULT);

        return future.get();

    }

    private static Integer submitBlockCallable() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newFixedThreadPool(1);

        Future<Integer> future = executorService.submit(new Callable<Integer>() {

            @Override

            public Integer call() throws Exception {

                System.out.println("This is submitBlockCallable");

                return RESULT;

            }

        });

        return future.get();// 阻塞

    }

    private static boolean submitNonBlockCallable() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newFixedThreadPool(1);

        Future<Integer> future = executorService.submit(new Callable<Integer>() {

            @Override

            public Integer call() throws Exception {

                System.out.println("This is submitNonBlockCallable");

                return RESULT;

            }

        });

        while (!future.isDone()) {// 非阻塞

            System.out.println(new Date());

        }

        return future.isDone();

    }

    private static String shutdown() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newFixedThreadPool(1);

        final StringBuilder sb = new StringBuilder();

        executorService.submit(new Callable<Integer>() {

            @Override

            public Integer call() throws Exception {

                Thread.sleep(10000);

                sb.append("This is shutdown");

                return RESULT;

            }

        });

        executorService.shutdown();

        return sb.toString();

    }

    private static String shutdownWithAwaitTermination() throws InterruptedException, ExecutionException {

        ExecutorService executorService = Executors.newFixedThreadPool(1);

        final StringBuilder sb = new StringBuilder();

        executorService.submit(new Callable<Integer>() {

            @Override

            public Integer call() throws Exception {

                Thread.sleep(10000);

                sb.append(THIS_IS_SHUTDOWN_WITH_AWAIT_TERMINATION);

                return RESULT;

            }

        });

        executorService.shutdown();

        executorService.awaitTermination(Integer.MAX_VALUE, TimeUnit.DAYS);

        return sb.toString();

    }

    private static int testForkJoinPool(List<Integer> list) throws InterruptedException, ExecutionException {

        ForkJoinPool forkJoinPool = new ForkJoinPool(8);

        Future<Integer> future = forkJoinPool.submit(new SumTask(list));

        return future.get();

    }

    @Test

    public void test() throws InterruptedException, ExecutionException {

        Assert.assertTrue(submitRunnable());

        Assert.assertEquals(RESULT, submitRunnableWithResult().intValue());

        Assert.assertEquals(RESULT, submitBlockCallable().intValue());

        Assert.assertTrue(submitNonBlockCallable());

        Assert.assertTrue(shutdown().isEmpty());

        Assert.assertEquals(THIS_IS_SHUTDOWN_WITH_AWAIT_TERMINATION, shutdownWithAwaitTermination());

        Assert.assertEquals(10, testForkJoinPool(Arrays.asList(new Integer[] { 1, 2, 3, 4 })));

        Assert.assertEquals(49, testForkJoinPool(Arrays.asList(new Integer[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 })));

        Assert.assertEquals(60, testForkJoinPool(Arrays.asList(new Integer[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 })));

    }

}

SumTask类如下：

import java.util.List;

import java.util.concurrent.RecursiveTask;

public class SumTask extends RecursiveTask<Integer> {

    private static final long serialVersionUID = 1L;

    private List<Integer> list;

    public SumTask(List<Integer> list) {

        this.list = list;

    }

    /**

     * Ensure it is necessary to divide the job to parts and finish them separately

     *

     * @return

     */

    @Override

    protected Integer compute() {

        int rtn, size = list.size();

        if (size < 10) {

            rtn = sum(list);

        } else {

            SumTask subTask1 = new SumTask(list.subList(0, size / 2));

            SumTask subTask2 = new SumTask(list.subList(size / 2 + 1, size));

            subTask1.fork();

            subTask2.fork();

            rtn = subTask1.join() + subTask2.join();

        }

        return rtn;

    }

    private int sum(List<Integer> list) {

        return list.stream().mapToInt(number -> number.intValue()).sum();

    }

}

Java多线程系列七——ExecutorService的更多相关文章

  1. java多线程系列(七)---Callable、Future和FutureTask

    Callable.Future和FutureTask 前言:如有不正确的地方,还望指正. 目录 认识cpu.核心与线程 java多线程系列(一)之java多线程技能 java多线程系列(二)之对象变量 ...

  2. 【Java多线程系列七】ExecutorService

    java.util.concurrent.ExecutorService接口提供了许多线程管理的方法 Method 说明 shutdown 拒绝接收新的任务,待已提交的任务执行后关闭,且宿主线程不阻塞 ...

  3. （Java多线程系列七）Java内存模型和线程的三大特性

    Java内存模型和线程的三大特性 多线程有三大特性:原子性.可见性.有序性 1.Java内存模型 Java内存模型(Java Memory Model ,JMM),决定一个线程对共享变量的写入时,能对 ...

  4. java多线程系列(八)---CountDownLatch和CyclicBarrie

    CountDownLatch 前言:如有不正确的地方,还望指正. 目录 认识cpu.核心与线程 java多线程系列(一)之java多线程技能 java多线程系列(二)之对象变量的并发访问 java多线 ...

  5. java多线程系列(九)---ArrayBlockingQueue源码分析

    java多线程系列(九)---ArrayBlockingQueue源码分析 目录 认识cpu.核心与线程 java多线程系列(一)之java多线程技能 java多线程系列(二)之对象变量的并发访问 j ...

  6. Java多线程系列--“JUC线程池”06之 Callable和Future

    概要 本章介绍线程池中的Callable和Future.Callable 和 Future 简介示例和源码分析(基于JDK1.7.0_40) 转载请注明出处:http://www.cnblogs.co ...

  7. Java多线程系列--“JUC锁”11之 Semaphore信号量的原理和示例

    概要 本章,我们对JUC包中的信号量Semaphore进行学习.内容包括:Semaphore简介Semaphore数据结构Semaphore源码分析(基于JDK1.7.0_40)Semaphore示例 ...

  8. Java多线程系列--“JUC线程池”01之 线程池架构

    概要 前面分别介绍了"Java多线程基础"."JUC原子类"和"JUC锁".本章介绍JUC的最后一部分的内容——线程池.内容包括:线程池架构 ...

  9. Java多线程系列--“JUC线程池”03之 线程池原理(二)

    概要 在前面一章"Java多线程系列--“JUC线程池”02之 线程池原理(一)"中介绍了线程池的数据结构,本章会通过分析线程池的源码,对线程池进行说明.内容包括:线程池示例参考代 ...

随机推荐

  1. hdu——3861 The King’s Problem

    The King’s Problem Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Other ...

  2. http_load分析（转）

    http://www.cnblogs.com/xuning/p/3954057.html 一.前言 http_load是一款测试web服务器性能的开源工具,从下面的网址可以下载到最新版本的http_l ...

  3. 洛谷 P3879 [TJOI2010]阅读理解

    P3879 [TJOI2010]阅读理解 题目描述 英语老师留了N篇阅读理解作业,但是每篇英文短文都有很多生词需要查字典,为了节约时间,现在要做个统计,算一算某些生词都在哪几篇短文中出现过. 输入输出 ...

  4. java基础 2 static关键字

    2. static关键字 变量:静态变量在内存中只存在一份,只在类第一次实例化时初始化一次,同时类所有的实例都共享静态变量,可以直接同过类名                    来访问他. 方法:静 ...

  5. Java日志框架-logback配置文件多环境日志配置（开发、测试、生产）（原始解决方法）

    说明:这种方式应该算是最通用的,原理是通过判断标签实现. <!-- if-then form --> <if condition="some conditional exp ...

  6. mysql too many connection 解决办法

    SHOW VARIABLES LIKE "max_connections"; SHOW VARIABLES LIKE "wait_timeout"; SET G ...

  7. Web容器自己主动对HTTP请求中參数进行URLDecode处理

    这篇文章转载自 : Web容器自己主动对HTTP请求中參数进行URLDecode处理 如题.在Java中或许非常多人都没有注意到当我们发送一个http请求时,假设附带的參数被URLEncode之后,到 ...

  8. php 获取TZ时间格式

    php将时间格式化成T Z的方法 gmdate("c") 这个函数的用法,学会了吧!!! <?php var_dump(gmdate("c")); ini ...

  9. 数据结构与算法问题 AVL二叉平衡树

    AVL树是带有平衡条件的二叉查找树. 这个平衡条件必须保持,并且它必须保证树的深度是O(logN). 一棵AVL树是其每一个节点的左子树和右子树的高度最多差1的二叉查找树. (空树的高度定义为-1). ...

  10. pat（A）1041. Be Unique（哈希）

    1.链接:点击打开链接 2.代码: #include<cstdio> #include<iostream> #include<cstring> using name ...