【发布时间】：2012-07-29 05:34:10
【问题描述】：
我真的需要你的帮助。我正在研究这个问题数周或数月。对于这篇冗长的帖子，我深表歉意，但我想尽可能准确地解释问题和我的设置。
我的 JAVA EE 6 Web 应用程序主要包含 3 个 Servlet：一个 javax.faces.webapp.FacesServlet、一个扩展 javax.servlet.http.HttpServlet 的 StreamingServlet 和一个 ClientServlet扩展 org.eclipse.jetty.websocket.WebSocketServlet。我想将 CDI 与这些 Servlet 一起使用，但它仅适用于 FacesServlet，更准确地说，适用于 JSF 操作路由到的 Bean。 CDI 注入不适用于其他 2 个 Servlet。
我的项目设置如下：Maven 3.0.4、Jetty 8.1.4 (jetty-maven-plugin)、MyFaces 2.1.6、Weld 1.1.8。
文件 pom.xml 包含 CDI 的依赖项：
...
<dependency>
<groupId>javax.enterprise</groupId>
<artifactId>cdi-api</artifactId>
<version>1.1.EDR1.2</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.annotation</groupId>
<artifactId>jsr250-api</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>org.jboss.weld.servlet</groupId>
<artifactId>weld-servlet</artifactId>
<version>${weld.version}</version>
<scope>runtime</scope>
</dependency>
...
文件 src/main/webapp/WEB-INF/beans.xml 只包含一个用于激活 CDI 的空 beans 元素：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/beans_1_0.xsd">
</beans>
文件 scr/main/webapp/WEB-INF/jetty-env.xml 包含用于通过 JNDI 获取 bean 管理器的 Jetty 特定配置：
<!DOCTYPE Configure PUBLIC "-//Mort Bay Consulting//DTD Configure//EN" "http://www.eclipse.org/jetty/configure.dtd">
<Configure id="webAppCtx" class="org.eclipse.jetty.webapp.WebAppContext">
<New id="BeanManager" class="org.eclipse.jetty.plus.jndi.Resource">
<Arg>
<Ref id="webAppCtx" />
</Arg>
<Arg>BeanManager</Arg>
<Arg>
<New class="javax.naming.Reference">
<Arg>javax.enterprise.inject.spi.BeanManager</Arg>
<Arg>org.jboss.weld.resources.ManagerObjectFactory</Arg>
<Arg />
</New>
</Arg>
</New>
</Configure>
文件 src/main/webapp/WEB-INF/web.xml 包含 servlet 侦听器和用于引导 CDI 的 BeanManager 参考：
...
<listener>
<listener-class>org.jboss.weld.environment.servlet.Listener</listener-class>
</listener>
<resource-env-ref>
<description>Object factory for the CDI Bean Manager</description>
<resource-env-ref-name>BeanManager</resource-env-ref-name>
<resource-env-ref-type>javax.enterprise.inject.spi.BeanManager</resource-env-ref-type>
</resource-env-ref>
...
通过这些设置，我在使用 mvn jetty:run 运行应用程序时总是遇到以下错误（第一行是最重要的）：
2012-07-31 11:09:33,546 [main] ERROR org.jboss.weld.environment.jetty.JettyPost72Container - Unable to create JettyWeldInjector. CDI injection will not be available in Servlets, Filters or Listeners
java.lang.IllegalArgumentException: Cannot load class for org.jboss.weld.environment.jetty.WeldDecorator
at org.jboss.weld.environment.servlet.util.Reflections.classForName(Reflections.java:58)
at org.jboss.weld.environment.jetty.JettyPost72Container.initialize(JettyPost72Container.java:66)
at org.jboss.weld.environment.servlet.Listener.contextInitialized(Listener.java:162)
at org.eclipse.jetty.server.handler.ContextHandler.callContextInitialized(ContextHandler.java:764)
at org.eclipse.jetty.servlet.ServletContextHandler.callContextInitialized(ServletContextHandler.java:406)
at org.eclipse.jetty.server.handler.ContextHandler.startContext(ContextHandler.java:756)
at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:242)
at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1234)
at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:699)
at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)
at org.mortbay.jetty.plugin.JettyWebAppContext.doStart(JettyWebAppContext.java:256)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
at org.eclipse.jetty.server.handler.HandlerCollection.doStart(HandlerCollection.java:224)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:167)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
at org.eclipse.jetty.server.handler.HandlerCollection.doStart(HandlerCollection.java:224)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:90)
at org.eclipse.jetty.server.Server.doStart(Server.java:262)
at org.mortbay.jetty.plugin.JettyServer.doStart(JettyServer.java:65)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
at org.mortbay.jetty.plugin.AbstractJettyMojo.startJetty(AbstractJettyMojo.java:511)
at org.mortbay.jetty.plugin.AbstractJettyMojo.execute(AbstractJettyMojo.java:364)
at org.mortbay.jetty.plugin.JettyRunMojo.execute(JettyRunMojo.java:516)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
Caused by: java.lang.NoClassDefFoundError: org/eclipse/jetty/servlet/ServletContextHandler$Decorator
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:415)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:377)
at org.jboss.weld.environment.servlet.util.Reflections.classForName(Reflections.java:51)
... 44 more
Caused by: java.lang.ClassNotFoundException: org.eclipse.jetty.servlet.ServletContextHandler$Decorator
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:415)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:377)
... 56 more
应用程序正在运行，但异常消息指出：CDI 注入在 Servlet 中不可用。
几天前，我发现了文章Starting a CDI webapp from Maven with Weld-Servlet and Jetty Plugin，尤其是允许在servlet 中注入的最后一招部分。作者解释说 Weld 需要装饰一些 Jetty 内部类，以便在 servlet 中使用 @Inject 注解，并且我们必须告诉 Jetty 类加载器在哪里可以找到此类，以便 Weld servlet 对其进行装饰。
我等待这个特殊信息已经等了很久。所以我添加了文件src/main/webapp/WEB-INF/jetty-context.xml：
<!DOCTYPE Configure PUBLIC "-//Jetty//Configure//EN" "http://www.eclipse.org/jetty/configure.dtd">
<Configure id="webAppCtx" class="org.eclipse.jetty.webapp.WebAppContext">
<Set name="serverClasses">
<Array type="java.lang.String">
<Item>org.eclipse.jetty.servlet.ServletContextHandler.Decorator</Item>
</Array>
</Set>
</Configure>
我还更新了 pom.xml 以合并文件 jetty-context.xml（最后一行）：
...
<plugin>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jetty-maven-plugin</artifactId>
<version>${jetty.version}</version>
<configuration>
<webApp>
<contextPath>/${project.build.finalName}</contextPath>
</webApp>
<jettyEnvXml>src/main/webapp/WEB-INF/jetty-env.xml</jettyEnvXml>
<contextXml>src/main/webapp/WEB-INF/jetty-context.xml</contextXml>
...
现在上面的错误消失了。在那短暂的一刻我很高兴:)
在 src/main/resources/log4j.properties 我增加了 Weld 的日志级别：
...
log4j.logger.org.jboss.weld=DEBUG, stdout
log4j.additivity.org.jboss.weld=false
...
启动应用程序时，我收到以下焊接日志消息：
...
2012-07-31 12:00:08,968 [main] INFO org.jboss.weld.Bootstrap - WELD-000101 Transactional services not available. Injection of @Inject UserTransaction not available. Transactional observers will be invoked synchronously.
2012-07-31 12:00:09,109 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000103 Enabled alternatives for Manager
Enabled alternatives: [] []
Registered contexts: [interface javax.enterprise.context.SessionScoped, interface javax.enterprise.context.ApplicationScoped, interface javax.enterprise.context.Dependent, interface javax.enterprise.context.RequestScoped, interface javax.enterprise.context.ConversationScoped, interface javax.inject.Singleton]
Registered beans: 0
: [] []
2012-07-31 12:00:09,109 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000104 Enabled decorator types for Manager
Enabled alternatives: [] []
Registered contexts: [interface javax.enterprise.context.SessionScoped, interface javax.enterprise.context.ApplicationScoped, interface javax.enterprise.context.Dependent, interface javax.enterprise.context.RequestScoped, interface javax.enterprise.context.ConversationScoped, interface javax.inject.Singleton]
Registered beans: 0
: []
2012-07-31 12:00:09,109 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000105 Enabled interceptor types for Manager
Enabled alternatives: [] []
Registered contexts: [interface javax.enterprise.context.SessionScoped, interface javax.enterprise.context.ApplicationScoped, interface javax.enterprise.context.Dependent, interface javax.enterprise.context.RequestScoped, interface javax.enterprise.context.ConversationScoped, interface javax.inject.Singleton]
Registered beans: 0
: []
2012-07-31 12:00:09,171 [main] INFO org.jboss.weld.environment.jetty.JettyPost72Container - Jetty7 detected, JSR-299 injection will be available in Listeners, Servlets and Filters.
2012-07-31 12:00:09,265 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Implicit Bean [javax.enterprise.inject.spi.InjectionPoint] with qualifiers [@Default]
2012-07-31 12:00:09,265 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: org.jboss.weld.bean-flat-Built-in-org.jboss.weld.context.DependentContext
2012-07-31 12:00:09,281 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.util.MediaType] with qualifiers [@Any @Default]
2012-07-31 12:00:09,281 [main] WARN org.jboss.weld.interceptor.util.InterceptionTypeRegistry - Class 'javax.ejb.PostActivate' not found, interception based on it is not enabled
2012-07-31 12:00:09,281 [main] WARN org.jboss.weld.interceptor.util.InterceptionTypeRegistry - Class 'javax.ejb.PrePassivate' not found, interception based on it is not enabled
2012-07-31 12:00:09,281 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.web.LoginBean] with qualifiers [@Any @Default]
2012-07-31 12:00:09,281 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: org.jboss.weld.bean-flat-Built-in-org.jboss.weld.context.http.HttpRequestContext
2012-07-31 12:00:09,281 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: org.jboss.weld.bean-flat-Built-in-org.jboss.weld.context.http.HttpSessionContext
2012-07-31 12:00:09,281 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.web.CustomerBean] with qualifiers [@Any @Default @Named]
2012-07-31 12:00:09,281 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: org.jboss.weld.bean-flat-Built-in-org.jboss.weld.context.bound.BoundConversationContext
2012-07-31 12:00:09,281 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: org.jboss.weld.bean-flat-Built-in-org.jboss.weld.context.ApplicationContext
2012-07-31 12:00:09,281 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.util.LocaleBean] with qualifiers [@Any @Default @Named]
2012-07-31 12:00:09,281 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: org.jboss.weld.bean-flat-Built-in-org.jboss.weld.context.bound.BoundRequestContext
2012-07-31 12:00:09,281 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: org.jboss.weld.bean-flat-Built-in-org.jboss.weld.context.SingletonContext
2012-07-31 12:00:09,281 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Implicit Bean [javax.enterprise.inject.Instance] with qualifiers [@Default]
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.DataReader] with qualifiers [@Any @Default @Named]
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.SessionBean] with qualifiers [@Any @Default @Named]
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.ConnectionTable] with qualifiers [@Any @Default @Named]
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: org.jboss.weld.bean-flat-Built-in-org.jboss.weld.context.http.HttpConversationContext
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.servlet.ClientServlet] with qualifiers [@Any @Default]
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: org.jboss.weld.bean-flat-Built-in-org.jboss.weld.context.RequestContext
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: org.jboss.weld.bean-flat-Built-in-javax.enterprise.context.Conversation
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Implicit Bean [javax.enterprise.event.Event] with qualifiers [@Default]
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.CustomerListBean] with qualifiers [@Any @Default]
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.Customer] with qualifiers [@Any @Default]
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.servlet.StreamingServlet] with qualifiers [@Any @Default]
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: org.jboss.weld.bean-flat-Built-in-org.jboss.weld.context.bound.BoundSessionContext
2012-07-31 12:00:09,296 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000106 Bean: Managed Bean [class de.telexiom.cardiom.SessionInfo] with qualifiers [@Any @Default]
2012-07-31 12:00:09,312 [main] DEBUG org.jboss.weld.Reflection - WELD-000601 interface javax.inject.Named is missing @Target. Weld will use this annotation, however this may make the application unportable.
2012-07-31 12:00:09,312 [main] DEBUG org.jboss.weld.Bootstrap - WELD-000100 Weld initialized. Validating beans
...
我使用Servlet 3.0 API，StreamingServlet 和ClientServlet 是通过注解配置的。问题是应用程序范围的 bean connectionTable 和 dataReader 没有被注入：
@WebServlet(value = "/stream", initParams = @WebInitParam(name = "maxIdleTime", value = "0"))
public class StreamingServlet extends HttpServlet
{
@Inject
private ConnectionTable connectionTable;
...
@WebServlet(value = "/push", loadOnStartup = 1, initParams = @WebInitParam(name = "maxIdleTime", value = "0"))
public class ClientServlet extends WebSocketServlet
{
@Inject
private ConnectionTable connectionTable;
@Inject
private DataReader dataReader;
...
调用（未）注入的属性，我总是得到 NullPointerExceptions。通过 web.xml 配置 Servlet 时，问题也仍然存在。我对自己做错了什么没有更多的想法。阅读所有关于 CDI 与 Jetty 和 Maven 结合的文章，我想知道我是否是唯一一个遇到这些注入问题的人。
在我的 JSF bean 类 UserBean.java 中，注入有效，我不必使用 setter 方法来初始化属性 connectionTable 和 dataReader。
在 DataReader 构造函数（以及 ConnectionTable 类）中使用以下输出语句
@ApplicationScoped
public class DataReader implements Serializable
{
...
public DataReader()
{
System.out.println("DataReader.DataReader(): " + this);
}
...
我想知道标准输出上显示的 2 个 DataReader 实例：
...
2012-07-31 14:03:04,843 [qtp5435124-17] DEBUG org.jboss.weld.JSF - WELD-000504 Resuming conversation with id null
31.07.2012 14:03:05 org.apache.myfaces.util.ExternalSpecifications isUnifiedELAvailable
INFO: MyFaces Unified EL support enabled
DataReader.DataReader(): DataReader$Proxy$_$$_WeldClientProxy@506e6d
ConnectionTable.ConnectionTable(): ConnectionTable$Proxy$_$$_WeldClientProxy@93b16c
2012-07-31 14:03:19,093 [qtp5435124-16] DEBUG org.jboss.weld.JSF - WELD-000504 Resuming conversation with id null
DataReader.DataReader(): DataReader@1cbd382
前 5 行在基于表单的身份验证后打印，最后 2 行在我的 JSF 操作第一次处理时出现，其中使用了注入的 dataReader 属性。由于 bean 是应用程序范围的，我真的很想知道 2 个构造函数传递。但从应用程序的行为来看，我认为没有任何问题。
我的最后一个假设是 servlet 以某种方式存在于分离的、独立的上下文或容器或类似的东西中。因为在其他 2 个 Servlet 中也无法获取 FacesContext：FacesContext.getCurrentInstance() 给出 null。但我不知道这在某种程度上是否重要。
我希望任何人都可以帮助我找出问题所在。提前谢谢你
塞巴斯蒂安
【问题讨论】：
-
这是我简单的 Jetty CDI 设置。我希望这成为一个提示。 gist.github.com/3613597
标签： jakarta-ee servlets jetty cdi jboss-weld