CDI注入在Servlet中不起作用 [英] CDI injection is not working in Servlets
问题描述
我真的需要你的帮助。我现在正在研究这个问题数周或数月。我为长篇文章道歉，但我想尽可能准确地解释问题和我的设置。
I really need your help. I'm working on this problem for weeks or months now. I apologize for the long post, but I want to explain the problem and my settings as precisely as possible.
我的JAVA EE 6 Web应用程序主要包含3个Servlet：a javax.faces.webapp.FacesServlet ，一个扩展 javax.servlet.http.HttpServlet 的StreamingServlet和一个扩展 org.eclipse.jetty.websocket.WebSocketServlet 。我想将CDI与这些Servlet一起使用，但它只适用于FacesServlet，更准确地说，适用于JSF动作路由到的Bean。 CDI注入不适用于其他2个Servlet。
My JAVA EE 6 web application mainly contains 3 Servlets: a javax.faces.webapp.FacesServlet, a StreamingServlet extending javax.servlet.http.HttpServlet and a ClientServlet extending org.eclipse.jetty.websocket.WebSocketServlet. I want to use CDI with these Servlets but it only works for the FacesServlet, to be more precisely, for the Beans the JSF actions are routed to. CDI injection doesn't work with the other 2 Servlets.
我项目的设置如下：Maven 3.0.4，Jetty 8.1.4（jetty-maven-插件），MyFaces 2.1.6，Weld 1.1.8。
The setup for my project is as follows: 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：
The file pom.xml contains the dependencies for CDI:
...
<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 仅包含用于激活CDI的空bean元素：
The file src/main/webapp/WEB-INF/beans.xml only contains an empty beans element for activating CDI:
<?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 包含通过JNDI获取bean管理器的Jetty特定配置：
The file scr/main/webapp/WEB-INF/jetty-env.xml contains the Jetty specific configuration for getting the bean manager via JNDI:
<!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 包含用于引导CDI的servlet侦听器和BeanManager引用：
The file src/main/webapp/WEB-INF/web.xml contains the servlet listener and the BeanManager reference for bootstrapping CDI:
...
<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>
...
使用这些设置我在运行应用程序时总是遇到以下错误 mvn jetty：run （第一行最重要）：
With these settings I always got the following error when running the application using mvn jetty:run (first line is most important):
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$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:415)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:377)
... 56 more
应用程序正在运行但是作为异常消息st ates：在Servlet中无法使用CDI注入。
The application was running but as the exception message states: CDI injection will not be available in Servlets.
几天前，我发现了这篇文章使用Weld-Servlet和Jetty插件从Maven启动CDI webapp 尤其是允许在servlet中注入的最后一招。作者解释说，Weld需要修饰一些Jetty内部类，以便在servlet中使用@Inject注释，并且我们必须告诉Jetty类加载器在哪里找到这个类，以便让Weld servlet来装饰它。
A couple of days ago, I found the article Starting a CDI webapp from Maven with Weld-Servlet and Jetty Plugin and especially the section Last trick to allow injection in servlets. The author explains that Weld needs to decorate some Jetty internal classes in order to use the @Inject annotation in servlets and that we have to tell the Jetty classloader where to find this class in order to have the Weld servlet to decorate it.
我等了很长时间才知道这些特殊信息。所以我添加了文件 src / main / webapp / WEB-INF / jetty-context.xml ：
I was waiting so long for this special information. So I added the file src/main/webapp/WEB-INF/jetty-context.xml:
<!DOCTYPE Configure PUBLIC "-//Jetty//Configure//EN" "http://www.eclipse.org/jetty/configure.dtd">
<Configure id="webAppCtx" class="org.eclipse.jetty.webapp.WebAppContext">
<Set name="serverClasses">
<Array type="java.lang.String">
<Item>org.eclipse.jetty.servlet.ServletContextHandler.Decorator</Item>
</Array>
</Set>
</Configure>
我还更新了 pom.xml 以合并文件码头-context.xml（最后一行）：
I also updated the pom.xml in order to incorporate the file jetty-context.xml (last line):
...
<plugin>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jetty-maven-plugin</artifactId>
<version>${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>
...
现在上述错误消失了。我很高兴这一短暂的时刻：）
Now the above error disappeared. I was so happy for that short moment :)
在src / main / resources / log4j.properties中我增加了Weld的日志级别：
In src/main/resources/log4j.properties I increased the log level for Weld:
...
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Weld日志消息：
When starting the application I get the following Weld log messages:
...
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通过注释配置。问题是不会注入应用程序作用域bean connectionTable 和 dataReader ：
I use the Servlet 3.0 API, the StreamingServlet and the ClientServlet are configured via annotations. The problem is that the application scoped beans connectionTable and dataReader are not injected:
@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，问题仍然存在。我对我做错了什么没有更多的想法。阅读关于CDI的所有文章以及Jetty和Maven，我想知道我是否是唯一一个有这些注入问题的文章。
Calling the (not) injected properties, I always get NullPointerExceptions. The problem also remains when configuring the Servlets via web.xml. I have no more ideas about what I am doing wrong. Reading all the articles about CDI in combination with Jetty and Maven, I wonder if I am the only one having these injection problems.
在我的JSF bean类中 UserBean .java 注入工作，我不必使用setter方法来初始化属性connectionTable和dataReader。
In my JSF bean class UserBean.java the injection works, I don't have to use setter methods for the properties connectionTable and dataReader to be initialized.
使用下面的输出语句DataReader构造函数（也在ConnectionTable类中）
Using the output statements below in the DataReader constructor (and also in the ConnectionTable class)
@ApplicationScoped
public class DataReader implements Serializable
{
...
public DataReader()
{
System.out.println("DataReader.DataReader(): " + this);
}
...
我想知道显示的2个DataReader实例stdout：
I wonder about the 2 DataReader instances which show up on stdout:
...
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
在基于表单的身份验证之后打印前5行，并且在我第一次处理JSF操作时出现最后2行使用注入的dataReader属性。由于bean是应用程序范围的，我真的很想知道2个构造函数的传递。但是从应用程序的行为来看，我认为它没有任何问题。
The first 5 lines are printed after form-based authentication and the last 2 lines appear when my JSF action is handled for the first time where the injected dataReader property is used. Since the beans are application scoped, I really wonder about the 2 constructor passes. But from the behavior of the application I think there is nothing wrong with it.
我的最后一个假设是servlet以某种方式生活在独立的，独立的上下文或容器之类的东西中那。因为也无法在其他2个Servlet中获取FacesContext： FacesContext.getCurrentInstance（）提供 null 。但我不知道这在某种程度上是否重要。
My last assumption is that the servlets somehow live in seperated, independent contexts or containers or something like that. Because it is also not possible to get the FacesContext in the 2 other Servlets: FacesContext.getCurrentInstance() gives null. But I don't know if this is important in some way.
我希望有人能帮助我找出问题所在。提前谢谢
I hope anyone can help me to figure out the problem. Thank you in advance
塞巴斯蒂安
推荐答案
嗯......你的配置看起来非常类似于我的。我不知道的是这个'java-web-api'maven artefact。我在一个新项目中检查了这个并且瞧...它有效。然后我先后添加了对JSF和WebSocket的支持，但它再次没有用。最后，我弄清楚错误是什么：我将'jetty-server'artefact添加为我的pom.xml的依赖项，但我没有设置范围。所以我使用了错误的服务器库或类似的东西。现在使用'提供'范围
Hm... your configuration looks very similar to mine. What I didn't know was this 'java-web-api' maven artefact. I checked this in a new project and voila... it works. Then I successively added support for JSF and WebSocket and it didn't work again. Finally, I figured out what the error was: I added the 'jetty-server' artefact as a dependency to my pom.xml but I didn't set a scope. So I was using the wrong server libs or something like that. Now when using the 'provided' scope
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-server</artifactId>
<version>${jetty.version}</version>
<scope>provided</scope>
</dependency>
一切似乎都有效，依赖注入也在servlet中工作。
everything seems to work and dependency injection is also working in servlets.
我还有两个关于你的pom的问题：
I have two more questions regarding your pom:
-
你不必设置< ; jettyEnvXml> Jetty Maven插件的元素？
Don't you have to set the <jettyEnvXml> element of the Jetty Maven plugin?
再次在Jetty Maven插件中使用< webAppConfig>元件。我正在使用< webApp>元素，因为这是Eclipse代码完成所知的。其中一个元素是否被弃用而有利于另一个？
Again in the Jetty Maven plugin you use the <webAppConfig> element. I was using the <webApp> element because this is known by the Eclipse code completion. Is one of these elements deprecated in favor of the other?
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