Struts2& Tiles：当apache.org关闭时，我的webapp无法启动 [英] Struts2 & Tiles: When apache.org is down my webapp fails to start
问题描述
我正在构建一个使用磁贴的Struts2 Web应用程序但是我发现了一个非常令人沮丧的问题，即如果apache.org失效（这似乎经常发生）Web应用程序无法启动。这是因为在其标准设置中，StrutsTilesListener尝试加载tiles defenitions文件，该文件包含一个带有public-id的DOCTYPE，该公共id指向位于tiles.apache.org上的DTD。
I am building a Struts2 web application which uses tiles however I have discovered a quite frustrating problem where if apache.org is down (which seems to happen quite regularly) the web application fails to start. This is because in its standard setup the StrutsTilesListener tries to load the tiles defenitions file which includes a DOCTYPE with a public-id which points to a DTD located on tiles.apache.org.
当应用程序启动时，使用Apache Xerces通过Apache Commons Digester加载定义文件，该文件试图从tiles.apache.org加载DTD但是如果apache.org是然后这就失败了，整个网络应用程序都无法启动。
When the application starts up the definition file is loaded using Apache Xerces via Apache Commons Digester which tries to load the DTD from tiles.apache.org but if apache.org is down then this fails and with it the whole web application wont start.
我可以通过下载文件并将其置于本地并指定新文件来绕过远程位置的下载struts定义文件中的本地位置，但是这个解决方案不是很方便，因为本地保存DTD的位置在不同的开发者机器上可能不同，一旦上传到实时环境就不同，所以我必须继续编辑位置webapp正在运行的机器很简单。
I can bypass the download from a remote location by downloading the file and placing it local and specifying the new local location in the struts definitions file, however this solution is not very portable as the location where the DTD is saved locally may be different on different developer machines and different once uploaded to a live environment so I would have to keep editing the location so suite the machine the webapp is running on which is just plain annoying.
项目中没有其他xml文件有这个问题，包括struts.xml文件也有DTD apache.org上的位置显然有一个设置问题，其中Tiles严格要求DTD但其他组件不是。这有什么解决方案吗？我已经没有耐心了，我不能把这个网络应用程序告知，如果我重启它时apache.org关闭，webapp就不会重新启动。
No other xml files in the project have this problem, including the struts.xml file which also has a DTD location on apache.org so clearly there is a setup problem where Tiles is strictly requiring the DTD but other components are not. Is there any solution to this? I am running out of patience and I cannot put this webapp live knowing that if apache.org is down when I restart it the webapp wont come back up.
Struts tile defenition file
Struts tiles defenition file
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE tiles-definitions PUBLIC
"-//Apache Software Foundation//DTD Tiles Configuration 2.1//EN"
"http://tiles.apache.org/dtds/tiles-config_2_1.dtd">
<tiles-definitions>
<definition name="master" template="/tiles/templates/master.jsp">
</definition>
<definition name="public" extends="master">
<put-attribute name="header" value="/tiles/templates/public/header.jsp" />
<put-attribute name="footer" value="/tiles/templates/public/footer.jsp" />
<put-attribute name="templateMeta" value="/tiles/templates/public/meta.jsp" />
</definition>
</tiles-definitions>
apache.org关闭时的Stacktrace
Stacktrace when apache.org is down
SEVERE: Exception sending context initialized event to listener instance of class org.apache.struts2.tiles.StrutsTilesListener
java.lang.IllegalStateException: Unable to instantiate container.
at org.apache.tiles.web.startup.TilesListener.contextInitialized(TilesListener.java:60)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3972)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4467)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:785)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:519)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:581)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
Caused by: org.apache.tiles.definition.DefinitionsFactoryException: I/O Error reading definitions.
at org.apache.tiles.definition.digester.DigesterDefinitionsReader.read(DigesterDefinitionsReader.java:273)
at org.apache.tiles.definition.UrlDefinitionsFactory.readDefinitions(UrlDefinitionsFactory.java:286)
at org.apache.tiles.definition.UrlDefinitionsFactory.init(UrlDefinitionsFactory.java:130)
at org.apache.tiles.impl.BasicTilesContainer.initializeDefinitionsFactory(BasicTilesContainer.java:406)
at org.apache.tiles.impl.BasicTilesContainer.init(BasicTilesContainer.java:130)
at org.apache.tiles.factory.TilesContainerFactory.initializeContainer(TilesContainerFactory.java:232)
at org.apache.tiles.factory.TilesContainerFactory.createTilesContainer(TilesContainerFactory.java:198)
at org.apache.tiles.factory.TilesContainerFactory.createContainer(TilesContainerFactory.java:163)
at org.apache.tiles.web.startup.TilesListener.createContainer(TilesListener.java:90)
at org.apache.struts2.tiles.StrutsTilesListener.createContainer(StrutsTilesListener.java:68)
at org.apache.tiles.web.startup.TilesListener.contextInitialized(TilesListener.java:57)
... 15 more
Caused by: java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.io.BufferedInputStream.fill(Unknown Source)
at java.io.BufferedInputStream.read1(Unknown Source)
at java.io.BufferedInputStream.read(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTP(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTP(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at org.apache.commons.digester.Digester.createInputSourceFromURL(Digester.java:2072)
at org.apache.commons.digester.Digester.resolveEntity(Digester.java:1725)
at com.sun.org.apache.xerces.internal.util.EntityResolverWrapper.resolveEntity(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.resolveEntityAsPerStax(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.dispatch(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
at org.apache.commons.digester.Digester.parse(Digester.java:1887)
at org.apache.tiles.definition.digester.DigesterDefinitionsReader.read(DigesterDefinitionsReader.java:267)
... 25 more
推荐答案
我发现了这个问题，这是我的错，我在问题中所说的一切都是真的，但这只是真的，因为DTD版本之间存在不匹配在tiles.xml文件中声明了我正在使用的tile的版本。
I have discovered the problem and it is my fault, everything I said in my question was true however it was only true because there was a mismatch between the DTD version that was declared in the tiles.xml file and the version of tiles I was using.
我实际上正在使用Tiles 2.0.6，但是从磁贴2.1引用了DTD，因此磁贴没有引用捆绑的DTD并尝试下载它。
I am actually using Tiles 2.0.6 but was referencing the DTD from tiles 2.1 so tiles was not referencing the bundled DTD and trying to download it instead.
<!DOCTYPE tiles-definitions PUBLIC
"-//Apache Software Foundation//DTD Tiles Configuration 2.1//EN"
"http://tiles.apache.org/dtds/tiles-config_2_1.dtd">
应该是
<!DOCTYPE tiles-definitions PUBLIC
"-//Apache Software Foundation//DTD Tiles Configuration 2.0//EN"
"http://tiles.apache.org/dtds/tiles-config_2_0.dtd">
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