tomcat7启动堆栈内存溢出、工程项目重复加载2次

短命女 2022-05-27 05:44 150阅读 0赞

今天我一同事在eclipse中部署工程后，启动tomcat7，出现2个奇怪问题：

**1、堆栈内存溢出**

提示“Possible root causes include a too low setting for -Xss and illegal cyclic inheritance dependencies”

严重: ContainerBase.addChild: start: 
    org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/OMAP]] 
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154) 
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901) 
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877) 
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633) 
    at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1114) 
    at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1673) 
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441) 
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) 
    at java.util.concurrent.FutureTask.run(FutureTask.java:138) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) 
    at java.lang.Thread.run(Thread.java:619) 
    Caused by: java.lang.IllegalStateException: Unable to complete the scan for annotations for web application [/mypro]. Possible root causes include a too low setting for -Xss and illegal cyclic inheritance dependencies
    at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:2109) 
    at org.apache.catalina.startup.ContextConfig.processAnnotationsJar(ContextConfig.java:1981) 
    at org.apache.catalina.startup.ContextConfig.processAnnotationsUrl(ContextConfig.java:1947) 
    at org.apache.catalina.startup.ContextConfig.processAnnotations(ContextConfig.java:1932) 
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1326) 
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:878) 
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:369) 
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119) 
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90) 
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5179) 
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) 
    ... 11 more 
    Caused by: java.lang.StackOverflowError 
    at java.util.HashMap.get(HashMap.java:300) 
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2257) 
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269) 
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269) 
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269) 
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269) 
    at org.apache.catalina.startup.ContextConfig.populateSCIsForCacheEntry(ContextConfig.java:2269) 
    ……

原因：

servlet3.1支持servlet注解，扫描jar包太深导致内存溢出

解决办法：

修改tomcat目录下conf/catalina.properties， 在tomcat.util.scan.DefaultJarScanner.jarsToSkip后添加“,\*”(前提是不使用servlet3.0的annotation支持)， 但是eclipse每次重新publish工程到tomcat时，会还原 catalina.properties文件，这时候只需要在eclipse中的Servers修改tomcat的catalina.propertes即可。

![70][]

**2、启动tomcat7后，一个工程项目会重复加载2次。**

原因：

tomcat部署工程项目时，部署在tomcat的webapps目录下，同时又会在conf/server.xml的<Host>节点中添加Context节点，该节点正好配置了该工程项目的路径。

那么tomcat加载时会加载webapps中的项目，又加载Context指定的项目，而导致了重复加载2次。这可能是eclipse有问题。

解决方法：

删除conf/server.xml的<Host>节点中添加Context节点。

但是eclipse每次重新publish工程到tomcat时，会还原server.xml文件，这时候只需要在eclipse中的Servers修改tomcat的server.xml即可。

![70][]

[70]: /images/20220527/c0c64b77f37c411396cbc322047cfa66.png