在我进行网页开发的过程中,我突然在Eclipse IDE中关闭了我的网页应用程序。大约一分钟后,我在Eclipse控制台中看到了一个警告。
WARNING: The web application [/Spring.MVC] registered the JDBC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
Sep 06, 2014 8:31:55 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
WARNING: The web application [/Spring.MVC] 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(Unknown Source)
com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:40)
Sep 06, 2014 8:32:00 PM org.apache.catalina.core.ApplicationContext log
INFO: No Spring WebApplicationInitializer types detected on classpath
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
Sep 06, 2014 8:32:00 PM org.apache.catalina.core.ApplicationContext log
INFO: Initializing Spring root WebApplicationContext
Sep 06, 2014 8:32:03 PM org.hibernate.jpa.internal.util.LogHelper logPersistenceUnitInformation
INFO: HHH000204: Processing PersistenceUnitInfo [
name: personPU
...]
到目前为止,它没有引起任何内存泄漏,我检查了我的VisualVM,一切都像往常一样,但是当我搜索更多关于这个问题的信息时,我意识到这个警告是由于MySQL驱动程序未释放资源或未正确关闭(我不知道如何准确地表达),然后我在SO上找到了这篇相关的文章。
而且,楼主是对的,"不用担心"的答案是不够的。这个警告让我烦恼,因为它可能会给我带来一些未来的持久性问题,这让我非常担心。我尝试了楼主编写的代码,但我遇到了一个问题:应该使用什么库使这段代码正常工作。这是我到目前为止的进展。
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Enumeration;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import org.hibernate.annotations.common.util.impl.LoggerFactory;
import com.mysql.jdbc.AbandonedConnectionCleanupThread;
@WebListener
public class ContextFinalizer implements ServletContextListener {
private static final Logger LOGGER = LoggerFactory.getLogger(ContextFinalizer.class);
public void contextInitialized(ServletContextEvent sce) {
}
public void contextDestroyed(ServletContextEvent sce) {
Enumeration<Driver> drivers = DriverManager.getDrivers();
Driver d = null;
while (drivers.hasMoreElements()) {
try {
d = drivers.nextElement();
DriverManager.deregisterDriver(d);
LOGGER.warn(String.format("Driver %s deregistered", d));
}
catch (SQLException ex) {
LOGGER.warn(String.format("Error deregistering driver %s", d), ex);
}
}
try {
AbandonedConnectionCleanupThread.shutdown();
}
catch (InterruptedException e) {
logger.warn("SEVERE problem cleaning up: " + e.getMessage());
e.printStackTrace();
}
}
}
我想知道我需要哪些库或者我是否正在使用正确的库来正确地实现这个项目,我甚至不知道应该使用什么日志记录器,感谢任何帮助。
AbandonedConnectionCleanupThread
正在关闭,但是,当我在我的VisualVM中监视服务器时,permgen空间仍然被占用,我仍然会遇到内存泄漏问题,我仍然需要执行手动GC
。但是就代码而言,它确实有效。 - Jeff