Facelet标签库机制无法按预期工作 [英] Facelet Tag Library mechanism does not work as expected

问题描述

我无法将标签库打包到战争文件中.我将标签从项目移到当前项目所依赖的额外库中.我将taglibrary文件放入包含标签的jar的META-INF目录中(

I'm unable to pack taglibrary in a war file. I moved tags from project to extra library the current project is depending now. I put the taglibrary file into the META-INF directory of the jar containing tags (how is described here). But the page does not work:

Expression Error: Named Object: eu.barbucha.barbatag.simple.PropertyTag not found.

服务器能够找到标签库.否则，该页面将起作用，只会显示一个警告:

The server is able to find the taglibrary. Otherwise the page works, just one waring appears:

Warning: This page calls for XML namespace http://barbucha.eu/tags declared with prefix br but no taglibrary exists for that namespace.

因此，问题是:为什么服务器仅找到描述符，而不找到类?当我将类从WEB-INF/lib/barbatag.jar复制到WEB-INF/classes并在管理控制台中重新启动Webapp时，页面开始工作.服务器还仅在UI组件直接涉及应用程序的类而不是不包含在WEB-INF/lib目录中存储的jar中时，才找到UI组件.另一方面，服务器从罐子中加载taglib描述符.真令人困惑...关键类的声明:

Thus the question is: Why the server finds just the descriptor, but not the classes? When I copy classes from WEB-INF/lib/barbatag.jar into WEB-INF/classes and restart the webapp in administration console, the page gets working. The server also finds UI-components only if they are involved directly in classes of the applictation, but not in the jar stored in the WEB-INF/lib directory. On other hand the server loads taglib descriptor from the jar. It's really confusing... Declaration of the critical class:

package eu.barbucha.barbatag.simple;    

@FacesComponent("eu.barbucha.barbatag.simple.PropertyTag")
public class PropertyTag extends UIComponentBase { ... }

关键标签的定义:

<tag>
    <display-name>The component taking values from a property file</display-name>
    <tag-name>property</tag-name>
    <component>
        <component-type>eu.barbucha.barbatag.simple.PropertyTag</component-type>
    </component>
</tag>

一个重要的要点:我正在使用Spring MVC.

One potentionally important point: I'm using Spring MVC.

推荐答案

您需要在JAR中提供一个/META-INF/faces-config.xml文件，以使JSF扫描JAR文件中具有JSF特定注释的类，例如@FacesComponent.这样做是为了防止JSF不必要地在每个单独的JAR文件中扫描类(如果您有很多类，这可能会非常浪费时间和CPU).

You need to supply a /META-INF/faces-config.xml file in the JAR in order to get JSF to scan the JAR file for classes with JSF specific annotations like @FacesComponent. This is done so to prevent JSF from unnecessarily scanning every single JAR file for classes (which might be very time and CPU consuming if you have lot of them).

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