用ThreadPoolExecutor的时候,又想知道被执行的任务的执行情况,这时就可以用FutureTask。
ThreadPoolTask
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package com.zuidaima.threadpool; |
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import java.io.Serializable; |
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import java.util.concurrent.Callable; |
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public class ThreadPoolTask implements Callable<String>, Serializable { |
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private static final long serialVersionUID = 0 ; |
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// 保存任务所需要的数据 |
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private Object threadPoolTaskData; |
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private static int consumeTaskSleepTime = 2000 ; |
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public ThreadPoolTask(Object tasks) { |
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this .threadPoolTaskData = tasks; |
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} |
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public synchronized String call() throws Exception { |
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// 处理一个任务,这里的处理方式太简单了,仅仅是一个打印语句 |
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System.out.println( "开始执行任务:" + threadPoolTaskData); |
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String result = "" ; |
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// //便于观察,等待一段时间 |
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try { |
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// long r = 5/0; |
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for ( int i = 0 ; i < 100000000 ; i++) { |
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} |
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result = "OK" ; |
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} catch (Exception e) { |
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e.printStackTrace(); |
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result = "ERROR" ; |
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} |
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threadPoolTaskData = null ; |
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return result; |
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} |
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} |
模拟客户端提交的线程
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package com.zuidaima.threadpool; |
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import java.util.concurrent.ExecutionException; |
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import java.util.concurrent.FutureTask; |
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import java.util.concurrent.TimeUnit; |
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import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor; |
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public class StartTaskThread implements Runnable { |
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private ThreadPoolTaskExecutor threadPoolTaskExecutor; |
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private int i; |
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public StartTaskThread(ThreadPoolTaskExecutor threadPoolTaskExecutor, int i) { |
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this .threadPoolTaskExecutor = threadPoolTaskExecutor; |
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this .i = i; |
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} |
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@Override |
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public synchronized void run() { |
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String task = "task@ " + i; |
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System.out.println( "创建任务并提交到线程池中:" + task); |
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FutureTask<String> futureTask = new FutureTask<String>( |
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new ThreadPoolTask(task)); |
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threadPoolTaskExecutor.execute(futureTask); |
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// 在这里可以做别的任何事情 |
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String result = null ; |
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try { |
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// 取得结果,同时设置超时执行时间为1秒。同样可以用future.get(),不设置执行超时时间取得结果 |
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result = futureTask.get( 1000 , TimeUnit.MILLISECONDS); |
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} catch (InterruptedException e) { |
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futureTask.cancel( true ); |
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} catch (ExecutionException e) { |
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futureTask.cancel( true ); |
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} catch (Exception e) { |
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futureTask.cancel( true ); |
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// 超时后,进行相应处理 |
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} finally { |
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System.out.println( "task@" + i + ":result=" + result); |
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} |
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} |
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} |
SPRING配置文件
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<?xml version= "1.0" encoding= "UTF-8" ?> |
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<beans xmlns= "http://www.springframework.org/schema/beans" |
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xmlns:xsi= "http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc= "http://www.springframework.org/schema/mvc" |
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xmlns:aop= "http://www.springframework.org/schema/aop" xmlns:context= "http://www.springframework.org/schema/context" |
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xsi:schemaLocation=" |
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http: //www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd |
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http: //www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd |
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http: //www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd |
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http: //www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd |
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"> |
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<bean id= "threadPoolTaskExecutor" |
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class = "org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor" > |
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<!-- 核心线程数,默认为 1 --> |
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<property name= "corePoolSize" value= "10" /> |
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<!-- 最大线程数,默认为Integer.MAX_VALUE --> |
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<property name= "maxPoolSize" value= "50" /> |
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<!-- 队列最大长度,一般需要设置值>=notifyScheduledMainExecutor.maxNum;默认为Integer.MAX_VALUE |
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<property name= "queueCapacity" value= "1000" /> --> |
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<!-- 线程池维护线程所允许的空闲时间,默认为60s --> |
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<property name= "keepAliveSeconds" value= "300" /> |
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<!-- 线程池对拒绝任务(无线程可用)的处理策略,目前只支持AbortPolicy、CallerRunsPolicy;默认为后者 --> |
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<property name= "rejectedExecutionHandler" > |
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<!-- AbortPolicy:直接抛出java.util.concurrent.RejectedExecutionException异常 --> |
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<!-- CallerRunsPolicy:主线程直接执行该任务,执行完之后尝试添加下一个任务到线程池中,可以有效降低向线程池内添加任务的速度 --> |
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<!-- DiscardOldestPolicy:抛弃旧的任务、暂不支持;会导致被丢弃的任务无法再次被执行 --> |
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<!-- DiscardPolicy:抛弃当前任务、暂不支持;会导致被丢弃的任务无法再次被执行 --> |
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<bean class = "java.util.concurrent.ThreadPoolExecutor$CallerRunsPolicy" /> |
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</property> |
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</bean> |
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</beans> |
测试类
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package com.zuidaima.test; |
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import org.junit.Test; |
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import org.junit.runner.RunWith; |
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import org.springframework.beans.factory.annotation.Autowired; |
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import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor; |
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import org.springframework.test.context.ContextConfiguration; |
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import org.springframework.test.context.junit4.AbstractJUnit4SpringContextTests; |
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import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; |
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import com.zuidaima.threadpool.StartTaskThread; |
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@RunWith (SpringJUnit4ClassRunner. class ) |
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// 指定的运行runner,并且把你所指定的Runner作为参数传递给它 |
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@ContextConfiguration (locations = "classpath*:applicationContext.xml" ) |
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public class TestThreadPool extends AbstractJUnit4SpringContextTests { |
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private static int produceTaskSleepTime = 10 ; |
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private static int produceTaskMaxNumber = 1000 ; |
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@Autowired |
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private ThreadPoolTaskExecutor threadPoolTaskExecutor; |
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public ThreadPoolTaskExecutor getThreadPoolTaskExecutor() { |
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return threadPoolTaskExecutor; |
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} |
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public void setThreadPoolTaskExecutor( |
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ThreadPoolTaskExecutor threadPoolTaskExecutor) { |
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this .threadPoolTaskExecutor = threadPoolTaskExecutor; |
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} |
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@Test |
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public void testThreadPoolExecutor() { |
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for ( int i = 1 ; i <= produceTaskMaxNumber; i++) { |
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try { |
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Thread.sleep(produceTaskSleepTime); |
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} catch (InterruptedException e1) { |
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e1.printStackTrace(); |
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} |
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new Thread( new StartTaskThread(threadPoolTaskExecutor, i)).start(); |
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} |
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} |
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} |
原文中有些纰漏,我已经修改
项目截图(基于maven构建)
运行截图:
如果遇到cpu忙执行超过1秒的会返回null