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用ThreadPoolExecutor的時候,又想知道被執(zhí)行的任務(wù)的執(zhí)行情況,這時就可以用FutureTask。
ThreadPoolTask
package com.paul.threadPool; import java.io.Serializable; import java.util.concurrent.Callable; public class ThreadPoolTask implements Callable<String>, Serializable { private static final long serialVersionUID = 0; // 保存任務(wù)所需要的數(shù)據(jù) private Object threadPoolTaskData; private static int consumeTaskSleepTime = 2000; public ThreadPoolTask(Object tasks) { this.threadPoolTaskData = tasks; } public synchronized String call() throws Exception { // 處理一個任務(wù),這里的處理方式太簡單了,僅僅是一個打印語句 System.out.println("開始執(zhí)行任務(wù):" + threadPoolTaskData); String result = ""; // //便于觀察,等待一段時間 try { // long r = 5/0; for ( int i= 0 ; i< 100000000 ; i++){ } result = "OK"; } catch (Exception e) { e.printStackTrace(); result = "ERROR"; } threadPoolTaskData = null; return result; } }
模擬客戶端提交的線程
package com.paul.threadPool; import java.util.concurrent.ExecutionException; import java.util.concurrent.FutureTask; import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor; public class StartTaskThread implements Runnable{ private ThreadPoolTaskExecutor threadPoolTaskExecutor; private int i; public StartTaskThread(ThreadPoolTaskExecutor threadPoolTaskExecutor,int i) { this.threadPoolTaskExecutor = threadPoolTaskExecutor; this.i = i; } @Override public synchronized void run() { String task = "task@ " + i; System.out.println("創(chuàng)建任務(wù)并提交到線程池中:" + task); FutureTask<String> futureTask = new FutureTask<String>( new ThreadPoolTask(task)); threadPoolTaskExecutor.execute(futureTask); // 在這里可以做別的任何事情 String result = null; try { // 取得結(jié)果,同時設(shè)置超時執(zhí)行時間為0.1秒。同樣可以用future.get(),不設(shè)置執(zhí)行超時時間取得結(jié)果 result = futureTask.get(); } catch (InterruptedException e) { futureTask.cancel(true); } catch (ExecutionException e) { futureTask.cancel(true); } catch (Exception e) { futureTask.cancel(true); // 超時后,進行相應(yīng)處理 } finally { System.out.println("task@" + i + ":result=" + result); } }
SPRING配置文件
<?xml version="1.0" encoding="UTF-8" ?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd"> <!-- 配置數(shù)據(jù)源 --> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" p:driverClassName="com.mysql.jdbc.Driver" p:url="jdbc:mysql://localhost:3306/mb_main?useUnicode=true&characterEncoding=UTF-8&useServerPrepStmts=true" p:username="root" p:password="1234" /> <!-- 配置Jdbc模板 --> <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate" p:dataSource-ref="dataSource" /> <!-- 事務(wù)管理器 --> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager" p:dataSource-ref="dataSource" /> <tx:advice id="jdbcTxAdvice" transaction-manager="transactionManager"> <tx:attributes> <tx:method name="*" /> </tx:attributes> </tx:advice> <!-- 使用aop/tx命名空間配置事務(wù)管理,這里對service包下的服務(wù)類方法提供事務(wù) --> <aop:config> <aop:pointcut id="jdbcServiceMethod" expression="within(com.baobaotao.service..*)" /> <aop:advisor pointcut-ref="jdbcServiceMethod" advice-ref="jdbcTxAdvice" /> </aop:config> <!-- 配置dao <bean id="loginLogDao" class="com.baobaotao.dao.LoginLogDao" p:jdbcTemplate-ref="jdbcTemplate" /> <bean id="userDao" class="com.baobaotao.dao.UserDao" p:jdbcTemplate-ref="jdbcTemplate" /> <bean id="userService" class="com.baobaotao.service.UserService" p:userDao-ref="userDao" p:loginLogDao-ref="loginLogDao" /> --> <bean id="threadPoolTaskExecutor" class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor"> <!-- 核心線程數(shù),默認為1 --> <property name="corePoolSize" value="10" /> <!-- 最大線程數(shù),默認為Integer.MAX_VALUE --> <property name="maxPoolSize" value="50" /> <!-- 隊列最大長度,一般需要設(shè)置值>=notifyScheduledMainExecutor.maxNum;默認為Integer.MAX_VALUE <property name="queueCapacity" value="1000" /> --> <!-- 線程池維護線程所允許的空閑時間,默認為60s --> <property name="keepAliveSeconds" value="300" /> <!-- 線程池對拒絕任務(wù)(無線程可用)的處理策略,目前只支持AbortPolicy、CallerRunsPolicy;默認為后者 --> <property name="rejectedExecutionHandler"> <!-- AbortPolicy:直接拋出java.util.concurrent.RejectedExecutionException異常 --> <!-- CallerRunsPolicy:主線程直接執(zhí)行該任務(wù),執(zhí)行完之后嘗試添加下一個任務(wù)到線程池中,可以有效降低向線程池內(nèi)添加任務(wù)的速度 --> <!-- DiscardOldestPolicy:拋棄舊的任務(wù)、暫不支持;會導致被丟棄的任務(wù)無法再次被執(zhí)行 --> <!-- DiscardPolicy:拋棄當前任務(wù)、暫不支持;會導致被丟棄的任務(wù)無法再次被執(zhí)行 --> <bean class="java.util.concurrent.ThreadPoolExecutor$CallerRunsPolicy" /> </property> </bean> </beans>
測試類
package com.paul.threadPool; import java.util.concurrent.ArrayBlockingQueue; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit; import org.junit.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor; import org.springframework.test.context.ContextConfiguration; import org.springframework.test.context.junit4.AbstractJUnit4SpringContextTests; @ContextConfiguration public class TestThreadPool extends AbstractJUnit4SpringContextTests{ private static int produceTaskSleepTime = 10; private static int produceTaskMaxNumber = 1000; @Autowired private ThreadPoolTaskExecutor threadPoolTaskExecutor; public ThreadPoolTaskExecutor getThreadPoolTaskExecutor() { return threadPoolTaskExecutor; } public void setThreadPoolTaskExecutor( ThreadPoolTaskExecutor threadPoolTaskExecutor) { this.threadPoolTaskExecutor = threadPoolTaskExecutor; } @Test public void testThreadPoolExecutor() { // 構(gòu)造一個線程池 final ThreadPoolExecutor threadPool = new ThreadPoolExecutor(2, 4, 600, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(3), new ThreadPoolExecutor.CallerRunsPolicy()); for (int i = 1; i <= produceTaskMaxNumber; i++) { try { Thread.sleep(produceTaskSleepTime); } catch (InterruptedException e1) { e1.printStackTrace(); } new Thread(new StartTaskThread(threadPoolTaskExecutor,i)).start(); } } }
項目截圖(基于maven構(gòu)建)
運行截圖:
如果遇到cpu忙執(zhí)行超過1秒的會返回null
總結(jié)
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