WebApplicationContext没有在Servlet Context重新加载时关闭

Question

当我关闭Tomcat时,我观察到Spring WebApplicationContext的正确关闭和清理.但是,当我重新部署基于Spring的WAR(通过将新WAR复制到webapps)时,不会发生正常关闭.由于所有随后的资源泄漏,这对我来说是一个问题:

org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [] appears to have started a thread named [hz.hazelcast-swipe-instance.scheduled] but has failed to stop it. This is very likely to create a memory leak.
org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [] appears to have started a thread named [hz.hazelcast-swipe-instance.operation.thread-0] but has failed to stop it. This is very likely to create a memory leak.

... 还有很多.我使用的是无XML配置,这是我的WebApplicationInitializer:

public class WebApplicationInitializer extends AbstractAnnotationConfigDispatcherServletInitializer
{
  @Override protected Class<?>[] getRootConfigClasses() {
    return new Class[] { WebSecurityConfig.class, WebMvcConfig.class };
  }
  @Override protected Class<?>[] getServletConfigClasses() { return null; }

  @Override protected String[] getServletMappings() { return new String[] { "/" }; }

  @Override public void onStartup(ServletContext ctx) throws ServletException {
    ctx.setInitParameter("spring.profiles.active", "production");
    super.onStartup(ctx);
  }
}

没有特定于在servlet上下文重新加载时控制行为的配置,我认为这应该是开箱即用的.

有没有办法在继续servlet上下文重新加载过程之前正确关闭WebApplicationContext？

我在Spring 4.0.5,Tomcat 7.0.54,Hazelcast 3.2.1,Hibernate 4.3.4.Final.

更新

我为ContextClosedEvent添加了一个Spring应用程序监听器,并打印了其调用的堆栈跟踪:

    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:333) [spring-context-4.0.6.RELEASE.jar:4.0.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:335) [spring-context-4.0.6.RELEASE.jar:4.0.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.doClose(AbstractApplicationContext.java:880) [spring-context-4.0.6.RELEASE.jar:4.0.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.close(AbstractApplicationContext.java:841) [spring-context-4.0.6.RELEASE.jar:4.0.6.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.destroy(FrameworkServlet.java:819) [spring-webmvc-4.0.6.RELEASE.jar:4.0.6.RELEASE]
    at org.apache.catalina.core.StandardWrapper.unload(StandardWrapper.java:1486) [catalina.jar:7.0.54]
    at org.apache.catalina.core.StandardWrapper.stopInternal(StandardWrapper.java:1847) [catalina.jar:7.0.54]
    at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232) [catalina.jar:7.0.54]
    at org.apache.catalina.core.StandardContext.stopInternal(StandardContext.java:5647) [catalina.jar:7.0.54]
    at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232) [catalina.jar:7.0.54]
    at org.apache.catalina.core.ContainerBase$StopChild.call(ContainerBase.java:1575) [catalina.jar:7.0.54]
    at org.apache.catalina.core.ContainerBase$StopChild.call(ContainerBase.java:1564) [catalina.jar:7.0.54]

这表明Spring关闭发生在它的Servlet#destroy方法中.这是相关的片段AbstractApplicationContext#close():

        if (logger.isInfoEnabled()) {
            logger.info("Closing " + this);
        }

        LiveBeansView.unregisterApplicationContext(this);

        try {
            // Publish shutdown event.
            publishEvent(new ContextClosedEvent(this));
        }
        catch (Throwable ex) {
            logger.warn("Exception thrown from ApplicationListener handling ContextClosedEvent", ex);
        }
        // Stop all Lifecycle beans, to avoid delays during individual destruction.
        try {
            getLifecycleProcessor().onClose();
        }
        catch (Throwable ex) {
            logger.warn("Exception thrown from LifecycleProcessor on context close", ex);
        }

        // Destroy all cached singletons in the context's BeanFactory.
        destroyBeans();

        // Close the state of this context itself.
        closeBeanFactory();

        // Let subclasses do some final clean-up if they wish...
        onClose();

        synchronized (this.activeMonitor) {
            this.active = false;
        }

我从这个片段的开头看到了日志条目,我得到了我的ContextClosedEvent.我也看到了一个条目DefaultLifecycleProcessor - Stopping beans in phase 2147483647,可能来自该getLifecycleProcessor.onClose()行.似乎在下游发生了一些错误.可能会吞下一些例外.

更新2

根据要求,这是我配置Hazelcast的方式:

@Bean(destroyMethod="shutdown") public HazelcastInstance hazelcast() {
  final Config c = hzConfig();
  final JoinConfig join = c.getNetworkConfig().getJoin();
  join.getMulticastConfig().setEnabled(false);
  join.getTcpIpConfig().setEnabled(true);
  return getOrCreateHazelcastInstance(c);
}

hzConfig() 是一种方法,其中配置实例名称,组名称和密码,映射名称和映射索引,所以我认为这不是一个有趣的方法.

这是我的Hibernate SessionFactory配置:

@Bean
public LocalSessionFactoryBean sessionFactory() {
  final LocalSessionFactoryBean b = new LocalSessionFactoryBean();
  b.setDataSource(dataSource);
  b.setHibernateProperties(props(
      "hibernate.connection.release_mode", "on_close",
      "hibernate.id.new_generator_mappings", "true",
      "hibernate.hbm2ddl.auto", "update",
      "hibernate.order_inserts", "true",
      "hibernate.order_updates", "true",
      "hibernate.max_fetch_depth", "0",
      "hibernate.jdbc.fetch_size", "200",
      "hibernate.jdbc.batch_size", "50",
      "hibernate.jdbc.batch_versioned_data", "true",
      "hibernate.jdbc.use_streams_for_binary", "true",
      "hibernate.use_sql_comments", "true"
  ));
  return b;
}

Answer 1

在某些时候,你提到有一个NoClassDefFoundError用于Logback.你通过删除这个依赖关系修复了这个问题,然后将问题转移到另一个类 - 一个Spring自己的类.

这可能意味着您拥有的任何一个库都会对类加载器造成错误,或者Tomcat可能需要指令不要对某些资源进行锁定.请在此处查看有关被锁定的Tomcat资源以及<Context>尝试的设置的更多信息:在Tomcat中将conf/context.xmla放置antiResourceLocking="true"到元素中.

Answer 2

你有没有尝试过unloadDelay为Tomcat上下文提升(默认为2000毫秒)？请参见http://tomcat.apache.org/tomcat-7.0-doc/config/context.html

更新:我发现你也遇到了logback的问题,尝试注册这个监听器也许值得注意:

class LogbackShutdownListener implements ServletContextListener {

    @Override
    public void contextDestroyed(ServletContextEvent event) {
        LoggerContext loggerContext = (LoggerContext)LoggerFactory.getILoggerFactory();
        System.out.println("Shutting down Logback context '" + loggerContext.getName() + "' for " + contextRootFor(event));
        loggerContext.stop();
    }

    @Override
    public void contextInitialized(ServletContextEvent event) {
        System.out.println("Logback context shutdown listener registered for " + contextRootFor(event));
    }

    private String contextRootFor(ServletContextEvent event) {
        return event.getServletContext().getContextPath();
    }

}

确保在spring上下文加载器侦听器之前声明此侦听器,以便在关闭时在上下文侦听器之后调用它.

更新2:也值得尝试注册另一个bean来手动关闭Hazelcast的东西(一定要从hazelcast bean中删除destroyMethod):

@Component
class HazelcastDestructor {

    @Autowired
    private HazelcastInstance instance;

    @PreDestroy
    public void shutdown() {
        try {
            instance.shutdown();
        } catch (Exception e) {
            System.out.println("Hazelcast failed to shutdown(): " + e);
            throw e;
        }
    }  
}

更新3:出于好奇,您是否尝试过并行部署:http://www.javacodegeeks.com/2011/06/zero-downtime-deployment-and-rollback.html.它可能与重新加载相同的上下文不同.至少你应该能够懒散地取消部署旧版本,看看是否有所作为.