如何@在WildFly 10中注入JMSContext？

Question

JavaEE7消息驱动bean的这段代码按预期接收消息，但无法发送回复，因为JMSContext始终为空。是什么原因导致注入失败？

我尝试了不同的方法来注入上下文，使用和不使用额外的@JMSConnectionFactory注释：

@JMSConnectionFactory("java:comp/DefaultJMSConnectionFactory")

或

@JMSConnectionFactory("java:/ConnectionFactory")

后者是管理web界面的JNDI屏幕中显示的值。

package com.example.wf10mdb;

import javax.annotation.Resource;
import javax.ejb.ActivationConfigProperty;
import javax.ejb.MessageDriven;
import javax.inject.Inject;
import javax.jms.JMSConnectionFactory;
import javax.jms.JMSContext;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;
import javax.jms.Topic;

@MessageDriven(activationConfig
        = {
            @ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Topic"),
            @ActivationConfigProperty(propertyName = "destination", propertyValue = "java:app/jms/topic/ExampleTopic")
        })
public class ChatMessageBean implements MessageListener {

    @Override
    public void onMessage(Message message) {
        try {

            final TextMessage textMessage = (TextMessage) message;
            final String question = textMessage.getText();

            System.out.println(question);

            if (null != question) {
                switch (question) {
                    case "Hello World!":
                        respond("Hello, Test Case!");
                        break;
                    case "How are you?":
                        respond("I'm doing well.");
                        break;
                    case "Still spinning?":
                        respond("Once every day, as usual.");
                        break;
                }
            }
        } catch (JMSException e) {
            throw new IllegalStateException(e);
        }
    }

    @Resource(mappedName = "java:/jms/topic/ExampleTopic")
    private Topic answerTopic;

    @Inject
    @JMSConnectionFactory("java:/ConnectionFactory")
    JMSContext context;

    public void respond(String txt) {
        if (context == null) {
            System.out.println("context is null");
            return;
        }

        try {
            context.createProducer().send(answerTopic, txt);
        } catch (Exception exc) {
            exc.printStackTrace(System.out);
        }
    }
}

Answer 1

这里有两个选项：

1. 使用作用域类型注释bean时，服务器会将应用程序识别为bean存档，不需要其他配置。
2. CDI使用名为beans.xml的可选部署描述符。归档文件必须仅在某些有限的情况下才包含beans.xml部署描述符(显式bean归档文件)，例如，当POJO类没有CDI注释时。

对于web应用程序，beans.xml部署描述符(如果存在)必须位于WEB-INF目录: webapp/WEB-INF/beans.xml对于EJB模块或JAR文件，beans.xml部署描述符(如果存在)必须位于META-INF目录: resources/META-INF/beans.xml

此文件可以为空：what is the purpose of including empty beans.xml in CDI implemenations projects?

打包CDI应用程序：https://docs.oracle.com/javaee/7/tutorial/cdi-adv001.htm

Answer 2

Wildfly 10默认情况下没有激活JMS组件。此配置只是'standalone-full.xml‘文件的一部分。如果你用标准的'standalone.xml‘运行Wildfly，你应该切换到standalone-full.xml配置。Wildfly正在使用Apache ActiveMQ。

这是一个带有自定义测试队列的messagin-activemq配置示例：

    ....
         <profile>
        .....
        <subsystem xmlns="urn:jboss:domain:messaging-activemq:1.0">
                    <server name="default">
                        <security-setting name="#">
                            <role name="guest" send="true" consume="true" create-non-durable-queue="true" delete-non-durable-queue="true"/>
                        </security-setting>
                        <address-setting name="#" dead-letter-address="jms.queue.DLQ" expiry-address="jms.queue.ExpiryQueue" max-size-bytes="10485760" page-size-bytes="2097152" message-counter-history-day-limit="10"/>
                        <http-connector name="http-connector" socket-binding="http" endpoint="http-acceptor"/>
                        <http-connector name="http-connector-throughput" socket-binding="http" endpoint="http-acceptor-throughput">
                            <param name="batch-delay" value="50"/>
                        </http-connector>
                        <in-vm-connector name="in-vm" server-id="0"/>
                        <http-acceptor name="http-acceptor" http-listener="default"/>
                        <http-acceptor name="http-acceptor-throughput" http-listener="default">
                            <param name="batch-delay" value="50"/>
                            <param name="direct-deliver" value="false"/>
                        </http-acceptor>
                        <in-vm-acceptor name="in-vm" server-id="0"/>
                        <jms-queue name="ExpiryQueue" entries="java:/jms/queue/ExpiryQueue"/>
                        <jms-queue name="DLQ" entries="java:/jms/queue/DLQ"/>
                        <connection-factory name="InVmConnectionFactory" connectors="in-vm" entries="java:/ConnectionFactory"/>
                        <connection-factory name="RemoteConnectionFactory" connectors="http-connector" entries="java:jboss/exported/jms/RemoteConnectionFactory"/>
                        <pooled-connection-factory name="activemq-ra" transaction="xa" connectors="in-vm" entries="java:/JmsXA java:jboss/DefaultJMSConnectionFactory"/>

                      <jms-queue name="testQueue"  entries="jms/queue/test java:jboss/exported/jms/queue/test" />
                    <jms-topic name="testTopic" entries="jms/topic/test java:jboss/exported/jms/topic/test" />
                    </server>
                </subsystem>
        ....

Answer 3

答案很简单:默认情况下，容器不会在消息驱动bean中注入依赖项。当我将@ApplicationScoped注释添加到bean类时，JMSContext将被注入。