如何在 JBoss 保险丝蓝图中使用多个属性占位符?

Question

我正在尝试在JBoss Fuse (6.3( 蓝图中使用etc目录中的多个属性文件。我的第一个方法如下：

<cm:property-placeholder persistent-id="foo" />
<cm:property-placeholder persistent-id="bar" />

我认为这是可行的，正如Red Hat文档中所描述的那样：

在蓝图中使用多个属性占位符

在蓝图 XML 文件中定义多个属性占位符(即定义引用不同持久 ID 的多个 cm：属性占位符元素(是合法的。但是，您需要注意的一件事是，如果来自不同属性占位符的两个属性具有相同的名称，则可能会发生冲突。在这种情况下，以下规则确定哪个属性优先：

1. 显式定义的属性设置(例如，在etc/PersistentID.cfg文件中定义(优先于默认属性设置(在cm:default-properties元素中定义(。

2. 如果给定属性有多个显式设置，则蓝图文件中最后一个属性占位符中的设置优先。

3. 默认属性设置(在cm:default-properties元素中定义(的优先级最低。

但后来我得到的错误Multiple placeholders with the same prefix and suffix are not allowed：

2018-05-15 17:43:59,065 | ERROR | /s42http1/deploy | BlueprintContainerImpl           | 22 - org.apache.aries.blueprint.core - 1.8.0 | Unable to start blueprint container for bundle myBlueprint/0.0.1.SNAPSHOT
org.osgi.service.blueprint.container.ComponentDefinitionException: Multiple placeholders with the same prefix and suffix are not allowed
at org.apache.aries.blueprint.ext.PlaceholdersUtils.validatePlaceholder(PlaceholdersUtils.java:49)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.blueprint.compendium.cm.CmNamespaceHandler.parsePropertyPlaceholder(CmNamespaceHandler.java:318)[20:org.apache.aries.blueprint.cm:1.1.0]
at org.apache.aries.blueprint.compendium.cm.CmNamespaceHandler.parse(CmNamespaceHandler.java:199)[20:org.apache.aries.blueprint.cm:1.1.0]
at org.apache.aries.blueprint.parser.Parser.parseCustomElement(Parser.java:1369)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.blueprint.parser.Parser.loadComponents(Parser.java:427)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.blueprint.parser.Parser.populate(Parser.java:331)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.blueprint.container.BlueprintContainerImpl.doRun(BlueprintContainerImpl.java:350)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.blueprint.container.BlueprintContainerImpl.run(BlueprintContainerImpl.java:277)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.blueprint.container.BlueprintExtender.createContainer(BlueprintExtender.java:300)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.blueprint.container.BlueprintExtender.createContainer(BlueprintExtender.java:269)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.blueprint.container.BlueprintExtender.createContainer(BlueprintExtender.java:265)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.blueprint.container.BlueprintExtender.modifiedBundle(BlueprintExtender.java:255)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.util.tracker.hook.BundleHookBundleTracker$Tracked.customizerModified(BundleHookBundleTracker.java:500)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.util.tracker.hook.BundleHookBundleTracker$Tracked.customizerModified(BundleHookBundleTracker.java:433)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.util.tracker.hook.BundleHookBundleTracker$AbstractTracked.track(BundleHookBundleTracker.java:725)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.util.tracker.hook.BundleHookBundleTracker$Tracked.bundleChanged(BundleHookBundleTracker.java:463)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.aries.util.tracker.hook.BundleHookBundleTracker$BundleEventHook.event(BundleHookBundleTracker.java:422)[22:org.apache.aries.blueprint.core:1.8.0]
at org.apache.felix.framework.util.SecureAction.invokeBundleEventHook(SecureAction.java:1127)[org.apache.felix.framework-4.4.1.jar:]
at org.apache.felix.framework.util.EventDispatcher.createWhitelistFromHooks(EventDispatcher.java:696)[org.apache.felix.framework-4.4.1.jar:]
at org.apache.felix.framework.util.EventDispatcher.fireBundleEvent(EventDispatcher.java:484)[org.apache.felix.framework-4.4.1.jar:]
at org.apache.felix.framework.Felix.fireBundleEvent(Felix.java:4429)[org.apache.felix.framework-4.4.1.jar:]
at org.apache.felix.framework.Felix.startBundle(Felix.java:2100)[org.apache.felix.framework-4.4.1.jar:]
at org.apache.felix.framework.BundleImpl.start(BundleImpl.java:976)[org.apache.felix.framework-4.4.1.jar:]
at org.apache.felix.fileinstall.internal.DirectoryWatcher.startBundle(DirectoryWatcher.java:1260)[10:org.apache.felix.fileinstall:3.6.4]
at org.apache.felix.fileinstall.internal.DirectoryWatcher.startBundles(DirectoryWatcher.java:1233)[10:org.apache.felix.fileinstall:3.6.4]
at org.apache.felix.fileinstall.internal.DirectoryWatcher.startAllBundles(DirectoryWatcher.java:1221)[10:org.apache.felix.fileinstall:3.6.4]
at org.apache.felix.fileinstall.internal.DirectoryWatcher.doProcess(DirectoryWatcher.java:515)[10:org.apache.felix.fileinstall:3.6.4]
at org.apache.felix.fileinstall.internal.DirectoryWatcher.process(DirectoryWatcher.java:365)[10:org.apache.felix.fileinstall:3.6.4]
at org.apache.felix.fileinstall.internal.DirectoryWatcher.run(DirectoryWatcher.java:316)[10:org.apache.felix.fileinstall:3.6.4]

所以我设置了placeholder-prefix和placeholder-suffix：

<cm:property-placeholder persistent-id="foo" />
<cm:property-placeholder persistent-id="bar" 
placeholder-prefix="$(" placeholder-suffix=")"/>

有了这个，我应该能够使用 $ { } 访问etc/foo.cfg，使用 $ ( ( 访问etc/bar.cfg属性，对吧？

不：

Caused by: java.io.IOException: Could not open $(bar_property) as a file, class path resource, or URL.
at org.apache.camel.util.jsse.JsseParameters.resolveResource(JsseParameters.java:182)[199:org.apache.camel.camel-core:2.17.0.redhat-630329]
at org.apache.camel.util.jsse.KeyStoreParameters.createKeyStore(KeyStoreParameters.java:174)[199:org.apache.camel.camel-core:2.17.0.redhat-630329]
at org.apache.camel.util.jsse.KeyManagersParameters.createKeyManagers(KeyManagersParameters.java:108)[199:org.apache.camel.camel-core:2.17.0.redhat-630329]
at org.apache.camel.util.jsse.SSLContextParameters.createSSLContext(SSLContextParameters.java:256)[199:org.apache.camel.camel-core:2.17.0.redhat-630329]
at org.apache.camel.component.http4.HttpComponent.createConnectionRegistry(HttpComponent.java:285)[296:org.apache.camel.camel-http4:2.17.0.redhat-630329]
at org.apache.camel.component.http4.HttpComponent.createEndpoint(HttpComponent.java:227)[296:org.apache.camel.camel-http4:2.17.0.redhat-630329]
at org.apache.camel.impl.DefaultComponent.createEndpoint(DefaultComponent.java:114)[199:org.apache.camel.camel-core:2.17.0.redhat-630329]
at org.apache.camel.impl.DefaultCamelContext.getEndpoint(DefaultCamelContext.java:569)[199:org.apache.camel.camel-core:2.17.0.redhat-630329]
... 36 more

我已经检查了bar_property是否存在于etc/bar.cfg.

那么如何在 JBoss 保险丝蓝图中使用多个属性占位符呢？我正在使用JBoss 保险丝 6.3.0.329。

Answer 1

当我输入这个问题时，我在 RedHat 文档(橡皮鸭调试;-(的引用部分的正上方找到了答案：

语法{{prefix}}将prefix变量的值替换为蓝图 XML 文件。OSGi 属性是使用以下 XML 元素设置的：

cm:property-placeholder
此元素允许您访问与指定的持久 ID 关联的属性。定义此元素后，可以使用语法{{PropName}}替换属于指定持久 ID 的变量。

cm:property-placeholder/cm:default-properties
您可以选择通过在cm:default-properties元素中定义cm:property元素来指定属性的默认值。但是，如果相应的etc/PersistentID.cfg文件定义了属性值，则将改用这些值。

因此，属性占位符的定义是正确的，如下所示：

<cm:property-placeholder persistent-id="foo" />
<cm:property-placeholder persistent-id="bar" 
placeholder-prefix="$(" placeholder-suffix=")"/>

但是在我的示例中，该属性必须与{{bar_property}}一起使用，而不是$(bar_property)。