tomcat启动时内存溢出问题--java.lang.OutOfMemoryError: PermGen space

在某次工程开发中，将web项目导入eclipse后，有时会遇到tomcat无法正确启动的问题，例如下面的内存溢出问题：

InitQueueThread is doWakeUp…..
workFlow ==== PubQueuetask List size is 0
Jun 27, 2017 9:44:14 AM org.apache.catalina.core.StandardContext filterStart

*SEVERE: Exception starting filter struts2
java.lang.OutOfMemoryError: PermGen space
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2527)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1010)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1483)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1361)
at com.opensymphony.xwork2.util.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:144)
at com.opensymphony.xwork2.ObjectFactory.getClassInstance(ObjectFactory.java:135)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.verifyAction(XmlConfigurationProvider.java:476)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addAction(XmlConfigurationProvider.java:429)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage(XmlConfigurationProvider.java:556)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages(XmlConfigurationProvider.java:295)
at org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages(StrutsXmlConfigurationProvider.java:112)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:264)
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:67)
at org.apache.struts2.dispatcher.Dispatcher.getContainer(Dispatcher.java:978)
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:446)
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:490)
at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:74)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:57)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:295)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:422)
at org.apache.catalina.core.ApplicationFilterConfig.(ApplicationFilterConfig.java:115)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3838)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4488)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:546)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:637)
at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:563)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:498)*

解决方法：在eclipse中，依次打开window–Preferences–Tomcat –JVM Settings，在Append to JVM Parameters选项中增加如下内容：
-Xms256m -Xmx512m -XX:PermSize=256m -XX:MaxPermSize=256m（具体大小视情况而定）。