java - JSF ApplicationScoped Bean 在 ServletContextListener 中使用 CDI 多次初始化

Question

问题是 ApplicationScoped bean 被初始化了很多次。在它确定为页面使用的稳定 bean 之前。如果使用应用程序范围来预加载配置并验证它。有一个过滤器，如果任何验证失败，它将转到“修复配置”页面。

我有一个 ServletContextInitlizer

import javax.inject.Inject;
import javax.servlet.ServletContextListener;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class StartupContextListener implements ServletContextListener {
    Logger logger = LogManager.getLogger(StartupContextListener.class.getName());
    @Inject 
    private BaseConfiguration baseConfiguration;

    public StartupContextListener() {
        super();
    }

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        logger.info("contextInitialized");
        try {       
            // Validate data directory
            baseConfiguration.getConfigPathFile(); // it validates
            //other validations
        } catch (Throwable t) {
            baseConfiguration.invalidateApplication("Application startup validation failed "+ t.getMessage(), t);
        }
        logger.info("Application started.");
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        logger.info("Redtape application shutting down.....");
    }
}

和

@ManagedBean(name="baseConfiguration",eager=true)
@ApplicationScoped
public class BaseConfiguration {    

    private File dataDirectory = null;
    private boolean validConfiguration=true;
    private String configurationMessage=null;

    Logger logger = LogManager.getLogger(BaseConfiguration.class.getName());

    public BaseConfiguration() {
        super();        
        logger.info(**"BaseConfiguration is CONSTRUCTED."**);
    }
    public String getConfigurationMessage() {
        return configurationMessage;
    }
    public boolean isValidConfiguration() {
        return validConfiguration;
    }   
    public void invalidateApplication(String message,Throwable t) {
        this.validConfiguration=false;
        this.configurationMessage=message;
        logger.fatal(message,t);
    }

    private String getConfigPathString() {      
        try {
            logger.info("Loading ["+BASE_PROPERTIES_FILE+"] file.");
            //validates a a configuration file
        } catch (IOException e) {           
            invalidateApplication("Unabled to load ["+BASE_PROPERTIES_FILE+"] from classpath.",e);
            return null;
        }
    }
}

maven 依赖项是

<properties>
    <weld.version>1.1.9.Final</weld.version>
    <weld.version></weld.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.glassfish.web</groupId>
        <artifactId>el-impl</artifactId>
        <version>2.2</version>
    </dependency>
    <dependency>
        <groupId>com.sun.faces</groupId>
        <artifactId>jsf-api</artifactId>
        <version>2.2.5</version>
    </dependency>
    <dependency>
        <groupId>com.sun.faces</groupId>
        <artifactId>jsf-impl</artifactId>
        <version>2.2.5</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
    </dependency>
    <dependency>
        <groupId>org.primefaces</groupId>
        <artifactId>primefaces</artifactId>
        <version>5.1</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>javax.servlet.jsp-api</artifactId>
        <version>2.3.1</version>
    </dependency>
    <dependency>
        <groupId>dk.heick.jhpropertiestyped</groupId>
        <artifactId>jhpropertiestyped</artifactId>
        <version>1.9</version>
    </dependency>
    <dependency>
        <groupId>org.primefaces.themes</groupId>
        <artifactId>all-themes</artifactId>
        <version>1.0.10</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-api</artifactId>
        <version>2.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-core</artifactId>
        <version>2.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-web</artifactId>
        <version>2.1</version>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.jboss.weld.servlet</groupId>
        <artifactId>weld-servlet</artifactId>
        <version>3.0.0.Alpha1</version>
    </dependency>
</dependencies>

我在日志中看到的内容。我得到 3 到 5 个构造函数已被调用。查找“BaseConfiguration 已构建”。下面。

jan. 12, 2015 6:28:39 PM org.jboss.weld.environment.servlet.EnhancedListener onStartup
INFO: WELD-ENV-001008: Initialize Weld using ServletContainerInitializer
jan. 12, 2015 6:28:40 PM org.jboss.weld.bootstrap.WeldStartup <clinit>
INFO: WELD-000900: 3.0.0 (Alpha1)
jan. 12, 2015 6:28:40 PM org.jboss.weld.environment.servlet.deployment.WebAppBeanArchiveScanner scan
WARN: WELD-ENV-001004: Found both WEB-INF/beans.xml and WEB-INF/classes/META-INF/beans.xml. It's not portable to use both locations at the same time. Weld is going to use file:/C:/Users/Frederik/Dropbox/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp3/wtpwebapps/dk.ionit.redtape.Redtape-1.0/WEB-INF/beans.xml.
jan. 12, 2015 6:28:40 PM org.jboss.weld.bootstrap.WeldStartup startContainer
INFO: WELD-000101: Transactional services not available. Injection of @Inject UserTransaction not available. Transactional observers will be invoked synchronously.
jan. 12, 2015 6:28:41 PM org.jboss.weld.interceptor.util.InterceptionTypeRegistry <clinit>
WARN: WELD-001700: Interceptor annotation class javax.ejb.PostActivate not found, interception based on it is not enabled
jan. 12, 2015 6:28:41 PM org.jboss.weld.interceptor.util.InterceptionTypeRegistry <clinit>
WARN: WELD-001700: Interceptor annotation class javax.ejb.PrePassivate not found, interception based on it is not enabled
jan. 12, 2015 6:28:41 PM org.jboss.weld.environment.tomcat.TomcatContainer initialize
INFO: WELD-ENV-001100: Tomcat 7+ detected, CDI injection will be available in Servlets, Filters and Listeners.
20150112 18:28:42.758 [localhost-startStop-1] WARN  dk.BaseConfiguration - BaseConfiguration is CONSTRUCTED.
"This is where it is constructed"........
    at dk.BaseConfiguration.<init>(BaseConfiguration.java:32) [BaseConfiguration.class:?]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_05]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) [?:1.8.0_05]
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) [?:1.8.0_05]
    at java.lang.reflect.Constructor.newInstance(Constructor.java:408) [?:1.8.0_05]
    at org.jboss.weld.injection.ConstructorInjectionPoint.newInstance(ConstructorInjectionPoint.java:113) [weld-servlet-3.0.0.Alpha1.jar:2014-10-01 17:10]
    ......
jan. 12, 2015 6:28:42 PM com.sun.faces.config.ConfigureListener contextInitialized
INFO: Initializing Mojarra 2.2.5 ( 20140108-1427 https://svn.java.net/svn/mojarra~svn/tags/2.2.5@12761) for context '/Redtape'
jan. 12, 2015 6:28:43 PM com.sun.faces.spi.InjectionProviderFactory createInstance
INFO: JSF1048: PostConstruct/PreDestroy annotations present.  ManagedBeans methods marked with these annotations will have said annotations processed.
jan. 12, 2015 6:28:44 PM com.sun.faces.config.ConfigureListener$WebConfigResourceMonitor$Monitor <init>
INFO: Monitoring file:/C:/Users/Frederik/Dropbox/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp3/wtpwebapps/dk.MyApp-1.0/WEB-INF/faces-config.xml for modifications
20150112 18:28:45.025 [localhost-startStop-1] WARN  dk..BaseConfiguration - BaseConfiguration is CONSTRUCTED.
"This is where it is constructed"........
    at dk.BaseConfiguration.<init>(BaseConfiguration.java:32) [BaseConfiguration.class:?]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_05]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) [?:1.8.0_05]
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) [?:1.8.0_05]
    at java.lang.reflect.Constructor.newInstance(Constructor.java:408) [?:1.8.0_05]
    at java.lang.Class.newInstance(Class.java:433) [?:1.8.0_05]
    at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:186) [jsf-impl-2.2.5.jar:2.2.5]    
    .......
jan. 12, 2015 6:28:45 PM org.primefaces.webapp.PostConstructApplicationEventListener processEvent
INFO: Running on PrimeFaces 5.1
jan. 12, 2015 6:28:45 PM org.jboss.weld.environment.servlet.Listener contextInitialized
INFO: WELD-ENV-001006: org.jboss.weld.environment.servlet.EnhancedListener used for ServletContext notifications
20150112 18:28:45.087 [localhost-startStop-1] INFO  dk.ionit.redtape.system.StartupContextListener - contextInitialized
20150112 18:28:45.087 [localhost-startStop-1] INFO  dk.ionit.redtape.system.StartupContextListener - Application starting.....
20150112 18:28:45.089 [localhost-startStop-1] INFO  dk.ionit.redtape.system.StartupContextListener - Application started.
jan. 12, 2015 6:28:45 PM com.sun.faces.config.ConfigureListener contextInitialized
INFO: Initializing Mojarra 2.2.5 ( 20140108-1427 https://svn.java.net/svn/mojarra~svn/tags/2.2.5@12761) for context '/Redtape'
jan. 12, 2015 6:28:45 PM com.sun.faces.spi.InjectionProviderFactory createInstance
INFO: JSF1048: PostConstruct/PreDestroy annotations present.  ManagedBeans methods marked with these annotations will have said annotations processed.
20150112 18:28:45.528 [localhost-startStop-1] WARN  dk.BaseConfiguration - BaseConfiguration is CONSTRUCTED.
java.lang.Exception
    at dk..BaseConfiguration.<init>(BaseConfiguration.java:32) [BaseConfiguration.class:?]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_05]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) [?:1.8.0_05]
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) [?:1.8.0_05]
    at java.lang.reflect.Constructor.newInstance(Constructor.java:408) [?:1.8.0_05]
    at java.lang.Class.newInstance(Class.java:433) [?:1.8.0_05] 
    at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:186) [jsf-impl-2.2.5.jar:2.2.5]    
    .......
20150112 18:28:45.529 [localhost-startStop-1] WARN  dk.ionit.redtape.system.BaseConfiguration - BaseConfiguration is CONSTRUCTED.
java.lang.Exception
    at dk..BaseConfiguration.<init>(BaseConfiguration.java:32) [BaseConfiguration.class:?]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_05]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) [?:1.8.0_05]
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) [?:1.8.0_05]
    at java.lang.reflect.Constructor.newInstance(Constructor.java:408) [?:1.8.0_05]
    at java.lang.Class.newInstance(Class.java:433) [?:1.8.0_05]
    at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:186) [jsf-impl-2.2.5.jar:2.2.5]
    .......
jan. 12, 2015 6:28:45 PM org.primefaces.webapp.PostConstructApplicationEventListener processEvent
INFO: Running on PrimeFaces 5.1
jan. 12, 2015 6:28:45 PM org.primefaces.webapp.PostConstructApplicationEventListener processEvent
INFO: Running on PrimeFaces 5.1
jan. 12, 2015 6:28:45 PM org.jboss.weld.environment.servlet.EnhancedListener contextInitialized
INFO: WELD-ENV-001009: org.jboss.weld.environment.servlet.Listener used for ServletRequest and HttpSession notifications
20150112 18:28:45.537 [localhost-startStop-1] WARN  dk.ionit.redtape.system.BaseConfiguration - BaseConfiguration is CONSTRUCTED.
java.lang.Exception
    at dk..BaseConfiguration.<init>(BaseConfiguration.java:32) [BaseConfiguration.class:?]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_05]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) [?:1.8.0_05]
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) [?:1.8.0_05]
    at java.lang.reflect.Constructor.newInstance(Constructor.java:408) [?:1.8.0_05]
    at org.jboss.weld.injection.ConstructorInjectionPoint.newInstance(ConstructorInjectionPoint.java:113) [weld-servlet-3.0.0.Alpha1.jar:2014-10-01 17:10]  
    .......
jan. 12, 2015 6:28:45 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-nio-8080"]
jan. 12, 2015 6:28:45 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-nio-8009"]
jan. 12, 2015 6:28:45 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 10658 ms

问题是:

我如何拥有一个 ApplicationScope 托管 bean，它仅加载一次，并且可以通过 EL 或 CDI 访问，它仅在 JSF 上下文中的 ServletContectListener 中构造一次。？？？？？？

提前感谢“有洞察力的专家”

Answer 1

您正在使用 CDI 来注入(inject)它，因此您应该使用

@Named
@ApplicationScoped

后者来自javax.enterprise.context包!

此外，您不应该依赖托管 bean 的构造函数，应使用如下方法:

@PostConstruct
public void init() {
...
}

正如您所期望的，这将被调用一次。