CountDownLatch实战

背景：单线程起动一个loader，loader中分多线程计算
1.单线程起loader,省略
2.多线程loader代码，AbstractDataCounterLoader 启动的线程，run 方法中抽象出calc 让子类实现

public class MutiThreadLoader extends AbstractDataCounterLoader {
	private static final Logger logger = LoggerFactory.getLogger(MutiThreadLoader.class);

	/**
	 * 线程数
	 */
	private int mutiThreadNum = 0;
	
	/**
	 * 处理类名
	 */
	private String handlerClassName;

	@Override
	protected boolean calc() {

		if (mutiThreadNum < 1) {
			return false;
		}
		CountDownLatch countDownLatch = new CountDownLatch(mutiThreadNum);
		List<AbstractHandler> mutiThreadLoaders = getMutiThreadLoaders(countDownLatch,
				mutiThreadNum);
		if (null == mutiThreadLoaders){
			return false;
		}
		ExecutorService exec = Executors.newFixedThreadPool(mutiThreadNum);
		for (int i = 0; i < mutiThreadNum; i++) {
			exec.submit(mutiThreadLoaders.get(i));
		}
		try {
			countDownLatch.await();
		} catch (InterruptedException e) {
			logger.error("InterruptedException:", e);
		}
		exec.shutdown();
		System.out.println("end");
		
		return true;
	}

	protected List<AbstractHandler> getMutiThreadLoaders(CountDownLatch countDownLatch,
			int mutiThreadNum) {
		List<AbstractHandler> mutiThreadLoaders = new ArrayList<AbstractHandler>();
		for (int i = 0; i < mutiThreadNum; i++) {
			AbstractHandler handler = getHandler();
			if (null == handler){
				return null;
			}
			handler.setThreadNum(i);
			handler.setCountDownLatch(countDownLatch);
			mutiThreadLoaders.add(handler);
		}
		return mutiThreadLoaders;
	}

	// 获得具体的处理类
	protected AbstractHandler getHandler(){
		AbstractHandler handler = null;
		try {
			handler = (AbstractHandler) Class.forName(handlerClassName).newInstance();
		} catch (InstantiationException e) {
			logger.error("getHandler error",e);
		} catch (IllegalAccessException e) {
			logger.error("getHandler error",e);
		} catch (ClassNotFoundException e) {
			logger.error("getHandler error",e);
		}
		return handler;
	}

	public int getMutiThreadNum() {
		return mutiThreadNum;
	}

	public void setMutiThreadNum(int mutiThreadNum) {
		this.mutiThreadNum = mutiThreadNum;
	}

	public String getHandlerClassName() {
		return handlerClassName;
	}

	public void setHandlerClassName(String handlerClassName) {
		this.handlerClassName = handlerClassName;
	}

}

2.spring配置
Xml配置例子：
<bean id="mutithreadLoaderTest" class="com.loader.muti.MutiThreadLoader">
                   <property name="dealTmRecordDao" ref="dealTmRecordDao"/>
                   <property name="spoutType" value=" mutithreadLoaderTest "/>
                   <!—主线程的loader频率—>
                   <property name="clacIntervalMinute" value="1"/>
        <!—线程数量—>
<property name="mutiThreadNum" value="10"/>
                   <!—具体的业务实现类名 这个类需要继承AbstractHandler—>
                   <property name="handlerClassName" value="com.loader.muti.HandlerTest"/>
         </bean>
3.业务实现类需要继承comloader.muti.AbstractHandler 实现execute方法

public class HandlerTest extends AbstractHandler{

	@Override
	protected void execute(int threadNum) {
		try {
			Thread.currentThread().sleep(1000);
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		System.out.println("---" + threadNum);
	}

}