tomcat6.0.28 内存溢出PermGen Space

我在tomcat 6.0.28 的servlet.xml设置了虚拟主机分了三个站点，

  .................

<Host name="www.ruijicn.com"  appBase="aaaapps"
　　　　　  unpackWARs="true" autoDeploy="true"
　　　　　  xmlValidation="false" xmlNamespaceAware="false">
　　　　　  <Context path="/china" docBase="f:\apache-tomcat-6.0.28\aaaapps" debug="0" reloadable="true" crossContext="true"/>
　　 </Host>

<Host name="bbs.ruijicn.com"  appBase="bbsapps"
　　　　　  unpackWARs="true" autoDeploy="true"
　　　　　  xmlValidation="false" xmlNamespaceAware="false">
　　　　　  <Context path="/bbschina" docBase="f:\apache-tomcat-6.0.28\bbsapps" debug="0" reloadable="true" crossContext="true"/>
　　 </Host>

...............

正常运行了一天多时间就报错

报Java head Space错误的，后我对bin目录下的catalina.bat 做了修改如下

rem ----- Execute The Requested Command ---------------------------------------
set JAVA_OPTS=-Xms128m -Xmx512m　 （这就是增加的地方，其他都没有变）
echo Using CATALINA_BASE:　 "%CATALINA_BASE%"
echo Using CATALINA_HOME:　 "%CATALINA_HOME%"
echo Using CATALINA_TMPDIR: "%CATALINA_TMPDIR%"
if ""%1"" == ""debug"" goto use_jdk
echo Using JRE_HOME:　　　  "%JRE_HOME%"
goto java_dir_displayed
:use_jdk
echo Using JAVA_HOME:　　　 "%JAVA_HOME%"
:java_dir_displayed
echo Using CLASSPATH:　　　 "%CLASSPATH%"

........

重启后又运行了一天，后开始报错 PermGen Space

 日记如下：[org.springframework.web.struts.ContextLoaderPlugIn] - Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mySessionFactory' defined in ServletContext resource [/WEB-INF/classes/applicationContext.xml]: Invocation of init method failed; nested exception is java.lang.OutOfMemoryError: PermGen space
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1337)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:473)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)
 at java.security.AccessController.doPrivileged(Native Method)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380)
 at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)
 at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:221)
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185)
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:423)
 at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:729)
 at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:381)
 at org.springframework.web.struts.ContextLoaderPlugIn.createWebApplicationContext(ContextLoaderPlugIn.java:354)
 at org.springframework.web.struts.ContextLoaderPlugIn.initWebApplicationContext(ContextLoaderPlugIn.java:295)
 at org.springframework.web.struts.ContextLoaderPlugIn.init(ContextLoaderPlugIn.java:225)
 at org.apache.struts.action.ActionServlet.initModulePlugIns(ActionServlet.java:869)
 at org.apache.struts.action.ActionServlet.init(ActionServlet.java:336)
 at javax.servlet.GenericServlet.init(GenericServlet.java:212)
 at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1172)
 at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:992)
 at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4058)
 at org.apache.catalina.core.StandardContext.start(StandardContext.java:4371)
 at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1116)
 at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1214)
 at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:293)
 at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
 at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1337)
 at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601)
 at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
 at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590)
 at java.lang.Thread.run(Thread.java:619)

忙活了一天，还是不知道怎么解决这个问题，还请大家多多指教！