小编Deb*_*Roy的帖子

这是在RHEL上的Java 7(51)上有24个内核我们注意到,当我们增加线程池大小时,包含在本地线程中的java SimpleDateFormat的平均响应时间会增加.这是预期的吗？或者,我只是在做一些愚蠢的事情？

测试程序

    public class DateFormatterLoadTest {
        private static final Logger LOG = Logger.getLogger(DateFormatterLoadTest .class);
        private final static int CONCURRENCY = 10;

        public static void main(String[] args) throws Exception {
            final AtomicLong total = new AtomicLong(0);
            ExecutorService es = Executors.newFixedThreadPool(CONCURRENCY);
            final CountDownLatch cdl = new CountDownLatch(CONCURRENCY);
            for (int i = 0; i < CONCURRENCY; i++) {
                es.execute(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            int size = 65000;
                            Date d = new Date();

                            long time = System.currentTimeMillis(); …

我在类路径中有commons-logging.jar(v1.0.4)和log4j-1.2.8.jar,并且遇到以下运行时错误:

Caused by: org.apache.commons.logging.LogConfigurationException: User-specified log class 'org.apache.commons.logging.impl.Log4JLogger' cannot be found or is not useable.
    at org.apache.commons.logging.impl.LogFactoryImpl.discoverLogImplementation(LogFactoryImpl.java:874)
    at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:604)
    at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:336)
    at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:310)
    at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:685)

问题陈述:我有一系列需要以并行方式处理的证券.在Java中,我使用线程池来处理每个安全性,并使用锁存器来倒计时.完成后我会做一些合并等.

所以我给我的SecurityProcessor(这是一个演员)发了消息,等待所有的期货完成.最后,我使用MergeHelper进行后处理.SecurityProcessor采用安全性,进行一些I/O处理并回复安全性

  val listOfFutures = new ListBuffer[Future[Security]]()
  var portfolioResponse: Portfolio = _
  for (security <- portfolio.getSecurities.toList) {
    val securityProcessor = actorOf[SecurityProcessor].start()
    listOfFutures += (securityProcessor ? security) map {
      _.asInstanceOf[Security]
    }
  }
  val futures = Future.sequence(listOfFutures.toList)
  futures.map {
    listOfSecurities =>
      portfolioResponse = MergeHelper.merge(portfolio, listOfSecurities)
  }.get

这个设计是否正确,是否有更好/更酷的方式来使用akka实现这个常见问题？

有没有计划利用java 7 util.concurrent的ForkJoin API,或者在Akka中公开类似的API？