Tomcat8 内存泄漏

2022-09-01 23:28:49

当我尝试在Java 8上停止tomcat8时,我得到了一些内存泄漏错误:

org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [ROOT] appears to have started a thread named [Abandoned connection cleanup thread] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 java.lang.Object.wait(Native Method)
 java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:142)
 com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:40)
23-Jan-2015 08:18:10.202 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [ROOT] appears to have started a thread named [pool-5-thread-1] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread


23-Jan-2015 08:18:10.205 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [ROOT] created a ThreadLocal with key of type [com.util.ThreadLocalProperties$1] (value [com.util.ThreadLocalProperties$1@2fafda6e]) and a value of type [java.util.Properties] (value [{}]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.

类 ThreadLocalProperties 是:

public class ThreadLocalProperties extends Properties {

    private static final long serialVersionUID = -4260632266508618756L;
    private final ThreadLocal<Properties> localProperties = new ThreadLocal<Properties>() {
        @Override
        protected Properties initialValue() {
            return new Properties();
        }
    };

    public ThreadLocalProperties(Properties properties) {
        super(properties);
    }

    @Override
    public String getProperty(String key) {
        String localValue = localProperties.get().getProperty(key);
        return localValue == null ? super.getProperty(key) : localValue;
    }

    @Override
    public Object setProperty(String key, String value) {
        return localProperties.get().setProperty(key, value);
    }

    public ThreadLocal<Properties> getThreadLocal() {
        return localProperties;
    }
}

我像这样开始和停止它:

@WebListener()
public class GeneralListener implements ServletContextListener {

    ThreadLocalProperties threadLocalProperties = new ThreadLocalProperties(System.getProperties());

    @Override
    public void contextDestroyed(ServletContextEvent arg0) {
        threadLocalProperties.getThreadLocal().remove();
    }

    @Override
    public void contextInitialized(ServletContextEvent arg0) {
        System.setProperties(threadLocalProperties);
    }
}

为什么我会得到所有这些内存泄漏错误?同样,当我运行关机时,它不会关闭它,我必须手动杀死进程。

怎么了?


答案 1

没什么可担心的。这是 tomcat 在检测到应用程序已启动自己的应用程序或创建.如果在关机时终止线程,并在不再需要线程局部时将其删除,则不会有问题。ThreadThreadLocal

为什么我会得到所有这些内存泄漏错误?同样,当我运行关机时,它不会关闭它,我必须手动杀死进程。

我已经看到了这种行为,当一个应用程序已经启动时(但这会发生在任何其他/上),并且没有关闭它。因此,请检查您是否在应用程序/服务器停止时关闭线程。ScheduledExecutorThreadTheadPoolcontextDestroyed

现在谈谈为什么服务器不停止的具体问题:JDBC驱动程序在JVM中注册为单例,并与所有Web应用程序共享。更多信息请点击这里。问题的最佳解决方案是将MySQL驱动程序移动到Tomcat的文件夹中。如果你不能做到这一点,你可以尝试一下,但它更像是一个黑客,而不是一个真正的解决方案。/lib


答案 2

我认为你的问题与此类似。当您重新部署应用程序时,apache会将其增量部署到不起作用的自身上,并且在开发阶段进行几次重新部署后,永久生成的空间会变满,并且您会收到内存泄漏错误。system.gc();

请在几次重新部署后继续重新启动服务器,以便可以通过重新启动来清除PermGen空间。

a 您也可以通过更改服务器中的PermGen空间来解决它。请访问此处

我希望这会帮助你。


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