spring的Scheduled（定时任务）和多线程

一、前言

在我们日常的开发中，经常用到数据同步的更新，这时我们采用的是spring的定时任务和java的多线程进行数据的更新，进行时实的服务调用。

二.实现思路

           1.创建线程类

           2.创建ExecutorService线程连接池

           3.调用线程池操作

           4.spring的Scheduled（定时任务）配置 

三.创建线程类

创建的线程类，我们采用的是实现Runnable接口，使用该类可以共享，在线程中要么继承Thread，或者实现Runnable接口，其中Thread是实现了Runnable的接口，实现Runnable接口可以更好的扩展和共享类，因为java是单继承多实现的程序。

public class ArchiveTask implements Runnable {

    /**
     * log.
     */
    private static Logger logger = LoggerFactory.getLogger(ArchiveTask.class);

    //注：由于spring事务配置采用的注解的方式来配置传播性配置，此类没有在spring传播配置里面，所以不能用自动装配的方式来配置
    private static FaxRecvArchiveCtrl faxRecvArchiveCtrl = AppContextAware.getBean(FaxRecvArchiveCtrl.class);

    private FaxRecvArchiveDTO faxRecvArchiveDTO;

    /**
     *  CountDownLatch是一个同步辅助类，在一组线程在执行操作之前，允许一个或多线程处于等待
     *  主要方法
     *          public CountDownLatch(int count);
     *          public void countDown();
     *          public void await() throws InterruptedException
     *
     *          构造方法参数指定了计数的次数
     *          countDown方法，当前线程调用此方法，则计数减一
     *          awaint方法，调用此方法会一直阻塞当前线程，直到计时器的值为0
     *
     */
    private CountDownLatch latch;

    public ArchiveTask(FaxRecvArchiveDTO faxRecvArchiveDTO, CountDownLatch latch) {
        this.faxRecvArchiveDTO = faxRecvArchiveDTO;
        this.latch = latch;
    }

    @Override
    public void run() {
        try {
            faxRecvArchiveCtrl.updateArchiveFileFlag(ServiceFactory.getCurrentSessionId(), faxRecvArchiveDTO);
        } catch (Exception ex) {
            logger.debug("["+this.faxRecvArchiveDTO.getFaxKey()+"]线程执行异常，错误信息为："+ex.getMessage());
        } finally{
            logger.debug("线程执行完："+this.faxRecvArchiveDTO.getFaxKey());
            latch.countDown();
        }
    }
}

 四、调用线程池操作

public class EasyFaxArchiveFileMgr {
	/**
	 * 日志
	 */
	Logger logger = LoggerFactory.getLogger(EasyFaxArchiveFileMgr.class);

	/**
	 * 线程池数量
	 */
	private int ThreadNum = 5;

	private static FaxRecvArchiveCtrl faxRecvArchiveCtrl = AppContextAware.getBean(FaxRecvArchiveCtrl.class);

	private static List<FaxRecvArchiveDTO> noArchiveList = new ArrayList<FaxRecvArchiveDTO>();

	public void archiveFile() throws ShineException{
		noArchiveList = faxRecvArchiveCtrl.getFaxRecvNoArchiveFile();

		ExecutorService executorService = Executors.newFixedThreadPool(ThreadNum);

		List<ArchiveTask> taskList = new ArrayList<ArchiveTask>();
		synchronized (noArchiveList) {
			while(CollectionUtils.isEmpty(noArchiveList) == false) {

				try {
					//定义计数器
					int countLatch = (noArchiveList.size() > ThreadNum) ? ThreadNum :noArchiveList.size();

					CountDownLatch latch = new CountDownLatch(countLatch);

					//组织任务
					for(int i = 0; i < ThreadNum; i++){
						if(CollectionUtils.isEmpty(noArchiveList) == false) {
							taskList.add(new ArchiveTask(noArchiveList.remove(0),latch));
						}else{
							break;
						}
					}
					//提交任务
					if (CollectionUtils.isEmpty(taskList) == false) {
						for (int i = 0, size = taskList.size(); i < size; i++) {
							executorService.submit(taskList.get(i));
						}
					}//等待所有线程都执行完
					latch.await();
				} catch(Exception ex) {
					logger.error("线程池处理出错，原因："+ex.getMessage());
				} finally {
					taskList.clear();
				}
                                //关闭线程连接池
				executorService.shutdown();
			}
		}

	}
}

五.spring配置

<?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:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-2.5.xsd">

	<bean id="timerFactory" class="org.springframework.scheduling.timer.TimerFactoryBean">
        <property name="scheduledTimerTasks">
            <list>
                <ref bean="archiveFileScheduler"/>
            </list>
        </property>
    </bean>
    <bean id="archiveFileScheduler" class="org.springframework.scheduling.timer.ScheduledTimerTask">
        <property name="delay">
            <!-- 启动30秒后开始运行 -->
            <value>30000</value>
        </property>
        <property name="period">
            <!-- 每10秒运行 -->
            <value>10000</value>
        </property>
        <property name="timerTask">
            <ref bean="archiveFileHandleMethodInvoker" />
        </property>
    </bean>

    <bean id="archiveFileHandleMethodInvoker" class="org.springframework.scheduling.timer.MethodInvokingTimerTaskFactoryBean">
        <property name="targetObject">
            <ref bean="com.shine.emofs.thirdparty.easyfax.ctrl.EasyFaxArchiveFileMgr" />
        </property>
        <property name="targetMethod">
            <value>archiveFile</value>
        </property>
    </bean>
</beans>

六、参考：

ExecutorService线程连接池：http://www.itzhai.com/the-executorservice-common-method-newfixedthreadpool-of-create-fixed-size-thread-pool.html#read-more