当我尝试在Java 8上停止tomcat8时,出现一些内存泄漏错误:
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.
ThreadLocalProperties类是:
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; } }
然后像这样启动和停止它:
@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); } }
为什么我会收到所有这些内存泄漏错误?同样,当我运行关闭程序时,它不会关闭它,我必须手动终止该进程。
怎么了?
不用担心。这是tomcat在检测到应用程序已启动Thread或自己创建的应用程序时输出的标准消息ThreadLocal。如果你终止关闭线程并删除 threadlocals 时不再需要它们,那么就没有问题。
Thread
ThreadLocal
我已经看到了这种现象,当应用程序启动时ScheduledExecutor(但是其他任何Thread/ 都会发生这种情况TheadPool),并且没有关闭它contextDestroyed。因此,请检查您是否在应用程序/服务器停止时关闭线程。
ScheduledExecutor
TheadPool
contextDestroyed
现在,在您的具体问题上, 为什么服务器不会停止:JDBC驱动程序在JVM中注册为单例,并与所有Web应用程序共享。更多信息在这里。最好的解决方案是将MySQL驱动程序移动到Tomcat的/lib文件夹中。如果您无法做到这一点,则可以尝试一下,但这更像是骇客,而不是真正的解决方案。
/lib