试用CountDownLatch的副成品，多线程群发邮件小程序

简要说明
1、基于javamail所做的批量发邮件小程序，SingleSender是普通发送，ThreadSender是多线程发送，MysqlSender是从数据库获取数据再调用ThreadSender来发送。
2、为啥写这个小程序呢？没啥特别的，只因最近想起thinking in java里面介绍的CountDownLatch类，为了练手多线程相关的技术而写了这个小程序，整个程序于我而言核心在ThreadSender里面的CountDownLatch。
3、jar依赖情况
1) 必须：activation.jar, mail.jar, commons-logging.jar, log4j-xx.jar, zTool-xx.jar(我写的另外一些小工具类，源码在 https://z-tool.googlecode.com/svn/trunk/zTool)
2) 可能需要：mysql-connector-java-xx.jar,velocity-xx-dep.jar
(注：上面版本号用xx代替了，依据实际情况找个合适的版本即可)

下面贴出SingleSender和ThreadSender的源码。详细源码在 https://github.com/auzll/zBatchSender

public final class SingleSender extends AbstractSender {private static final Log LOG = LogFactory.getLog(SingleSender.class);/** * 发送一批邮件 * @param entities 邮件实体列表 */public final List<MailEntity> send(List<MailEntity> entities) {int entitiesSize = null != entities ? entities.size() : 0;if (LOG.isInfoEnabled()) {LOG.info("method:send,entitiesSize:" + entitiesSize+ ",senderParam:[" + this.toSimpleLog() + "]"+ ",thread:" + Thread.currentThread().toString());}if (entitiesSize < 1) {return entities;}/** TODO Test code begin */// 模拟测试一下好了，不做实际发信for (MailEntity entity : entities) {try {TimeUnit.SECONDS.sleep(new Random().nextInt(3));} catch (InterruptedException e) {}if (LOG.isInfoEnabled()) {LOG.info("method:send,result:success,entity:[" + entity.toSimpleLog() + "],thread:" + Thread.currentThread().toString());}}if (true) return entities;/** TODO Test code end */Transport transport = null;Session session = null;int curTimes = 0;Properties sessionProperties = newProperties();for (MailEntity entity : entities) {try {if (null == transport || !transport.isConnected() || curTimes == transportUsingTimes) {if (null != transport && transport.isConnected()) {transport.close();}session = Session.getInstance(sessionProperties);transport = session.getTransport(new URLName("smtp",smtpHost, smtpPort, null, from.getAddress(), password)); // 获取新的transportcurTimes = 0;transport.connect(); if (LOG.isDebugEnabled()) {LOG.debug("method:send,desc:transport connect,thread:" + Thread.currentThread().toString());}}MimeMessage message = new MimeMessage(session);if (null != from) {message.setFrom(from);}if (null != entity.getTo()) {message.addRecipient(RecipientType.TO, entity.getTo());}if (null != entity.getCcTo()) {message.addRecipient(RecipientType.CC, entity.getCcTo());}if (null != entity.getBccTo()) {message.addRecipient(RecipientType.BCC, entity.getBccTo());}if (null != subject) {message.setSubject(subject);}if (null != entity.getContent()) {message.setText(entity.getContent(), charset);} else if (null != content) {message.setText(content, charset);} // 发送邮件transport.sendMessage(message, message.getAllRecipients());// 成功发送entity.setSuccess(true);if (LOG.isInfoEnabled()) {LOG.info("method:send,result:success,entity:[" + entity.toSimpleLog() + "],thread:" + Thread.currentThread().toString());}} catch (Exception e) {// 发送失败entity.setSuccess(false);if (LOG.isDebugEnabled()) {LOG.debug("method:send,result:fail,entity:[" + entity.toSimpleLog()+ "],thread:" + Thread.currentThread().toString(), e);} else {LOG.info("method:send,result:fail,entity:[" + entity.toSimpleLog() + "],thread:" + Thread.currentThread().toString() + ",e:" + e.getMessage());}} finally {curTimes++;}}if (null != transport && transport.isConnected()) {try {transport.close();} catch (Exception e) {LOG.info("method:send,desc:close transport,thread:" + Thread.currentThread().toString() , e);}}return entities;}/** * 发送一封邮件 * @param entity 邮件实体 */public final MailEntity send(MailEntity entity) {List<MailEntity> entities = new ArrayList<MailEntity>();entities.add(entity);send(entities);return entity;}private Properties newProperties() {String address = from.getAddress();String host = address;int atIndex = address.indexOf('@');if (-1 != atIndex) {host = address.substring(atIndex + 1);}Properties props = new Properties();props.put("mail.smtp.localhost", host);props.put("mail.from", address);props.put("mail.debug", mailDebug);if (null != password) {props.put("mail.smtp.auth", true);}return props;}}

public final class ThreadSender extends AbstractSender {private static final Log LOG = LogFactory.getLog(ThreadSender.class);private class Worker implements Runnable {private CountDownLatch latch;private List<MailEntity> entities;public Worker(CountDownLatch latch, List<MailEntity> entities) {this.latch = latch;this.entities = entities;}public void run() {new SingleSender().charset(charset).smtpHost(smtpHost).smtpPort(smtpPort).transportUsingTimes(transportUsingTimes).from(from).password(password).subject(subject).content(content).send(entities);if (LOG.isDebugEnabled()) {LOG.debug("method:Worker$run,desc:latch count down,thread:" + Thread.currentThread().toString());}latch.countDown();}}/** 默认的最大线程数量：Runtime.getRuntime().availableProcessors() * 2 */public static final int DEFAULT_THREAD_SIZE = Runtime.getRuntime().availableProcessors() * 2;/** 每个线程单次任务默认的发送邮件量 */public static final int DEFAULT_TASK_OF_EACH_THREAD = 10;/** 线程数量 */private int threadSize = DEFAULT_THREAD_SIZE;/** 每个线程单次任务最大发送邮件量 */private int taskOfEachThread = DEFAULT_TASK_OF_EACH_THREAD;private ExecutorService executorService;/** 是否在发送邮件后关闭executorService，若executorService由外界传入就不关闭，否则关闭 */private boolean shutdownExecutor = false;public ThreadSender() {this(Executors.newCachedThreadPool());this.shutdownExecutor = true;}public ThreadSender(ExecutorService executorService) {this.executorService = executorService;}/** * 发送一批邮件 * @param entities 邮件实体列表 */public final List<MailEntity> send(List<MailEntity> entities) {int entitiesSize = null != entities ? entities.size() : 0;if (LOG.isInfoEnabled()) {LOG.info("method:send,entitiesSize:" + entitiesSize+ ",thread:" + Thread.currentThread().toString());}if (entitiesSize < 1) {return entities;}int maxTask = threadSize * taskOfEachThread;if (entities.size() > maxTask) {throw new BatchSendException("Too much task, max is " + maxTask + ", current is " + entities.size());}int i = 0, toIndex = 0, len = entities.size();int count = len / taskOfEachThread;if (len % taskOfEachThread > 0) {count++;}CountDownLatch latch = new CountDownLatch(count);int realCount = 0;while (i < len) {if (LOG.isDebugEnabled()) {LOG.debug("method:send,desc:split task,taskIndex:" + realCount);}toIndex = i + taskOfEachThread;if (toIndex > len) {toIndex = len;}executorService.execute(new Worker(latch, entities.subList(i, toIndex)));i = toIndex;realCount++;}if (count != realCount) {throw new BatchSendException("Unexpected error[count != realCount], count is " + count + ", realCount is " + realCount);}try {if (LOG.isDebugEnabled()) {LOG.debug("method:send,desc:begin await,thread:" + Thread.currentThread().toString());}latch.await();if (LOG.isDebugEnabled()) {LOG.debug("method:send,desc:finish await,thread:" + Thread.currentThread().toString());}} catch (InterruptedException e) {throw new BatchSendException(e);}if (shutdownExecutor) {if (LOG.isDebugEnabled()) {LOG.debug("method:send,desc:try shutdown executorService,thread:" + Thread.currentThread().toString());}executorService.shutdownNow();}return entities;}public ThreadSender taskOfEachThread(int taskOfEachThread) {this.taskOfEachThread = taskOfEachThread;return this;}public ThreadSender threadSize(int threadSize) {this.threadSize = threadSize;return this;}}