Spring с RabbitMq и конфигурацией Apache Commons: конструктор выдал исключение; вложенным исключением является java.lang.NullPointerException

Я просто пытаюсь автоматически подключить следующего потребителя rabbitmq:

@Component
public class SmsQueueConsumer {

     //NOT SURE IF/ WHY THE CONFIG IS NULL...
     @Autowired
     Configuration config;

    public SmsQueueConsumer() throws Exception {

        //THIS IS WHERE THE NULL POINTER OCCURS (stack trace refers to line 54)
        String rabbitMqHost = config.getString("rabbitMq.hostName");

        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost(rabbitMqHost);
        com.rabbitmq.client.Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(queueName, false, false, false, null);

        Consumer consumer = new DefaultConsumer(channel) {

            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties, byte[] body) throws IOException {
             //... handle deliv logic
        };
    }

}

Приведенный выше класс автоматически подключается к классу реализации службы:

@Service
public class ServiceImpl implements Service {

    //HERE IS THE ABOVE CLASS BEING AUTOWIRED
    @Autowired(required=true)
    private SmsQueueConsumer queueConsumer;

    //NOTE THAT I ALSO AUTOWIRE THE CONFIG HERE TOO!
    @Autowired(required=true)
    private Configuration config;

    @Override
    public ServiceResponse doStuff(MyCoObj obj) throws Exception
    {
         //...
         queueSmsMessage(simpleMessage);
         //...
    }
    private void queueSmsMessage(SimpleSmsMessage simpleSmsMessage) {

        String rabbitMqHostName = config.getString("rabbitMq.hostName");
        String smsQueueName = config.getString("auctions.sms.queue.name");

        Gson gson = new Gson();
        String smsMessageJson = gson.toJson(simpleSmsMessage);

        try {
            ConnectionFactory factory = new ConnectionFactory();
            factory.setHost(rabbitMqHostName);
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();

            channel.queueDeclare(smsQueueName, false, false, false, null);
            channel.basicPublish("", smsQueueName, null, smsMessageJson.getBytes());

            channel.close();
            connection.close();
        } catch (Exception e) {
            logger.warn("sms message could not be queued.  TODO retry"); // TODO 
        }

    }

}

Я настроил testApplicationContext, чтобы включить необходимые компоненты

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
  xmlns:context="http://www.springframework.org/schema/context"
  xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:jee="http://www.springframework.org/schema/jee"
  xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx"
  xmlns:util="http://www.springframework.org/schema/util"
  xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
    http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.0.xsd
    http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.0.xsd
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
    http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd">

  <context:component-scan base-package="com.myCompany.basePackageToScan" />
  <context:annotation-config />
    <bean id="config" class="org.apache.commons.configuration.PropertiesConfiguration">
        <constructor-arg value = "some.properties"/>
    </bean>

    <bean id="smsQueueConsumer" class="com.myCompany.basePackageToScSmsQueueConsumer" />

</beans>

Когда я запускаю тест, я получаю следующую трассировку стека:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'smsQueueConsumer' defined in class path resource [testApplicationContext.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.myCompany.basePackageToScan.SmsQueueConsumer]: Constructor threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1101)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1046)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:755)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:125)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:60)
    at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.delegateLoading(AbstractDelegatingSmartContextLoader.java:109)
    at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext(AbstractDelegatingSmartContextLoader.java:261)
    at org.springframework.test.context.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:68)
    at org.springframework.test.context.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:86)
    at org.springframework.test.context.DefaultTestContext.getApplicationContext(DefaultTestContext.java:72)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:117)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:212)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:200)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:259)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:261)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:219)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:83)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:68)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:163)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.myCompany.basePackageToScan.SmsQueueConsumer]: Constructor threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:163)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:89)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1094)
    ... 43 more
Caused by: java.lang.NullPointerException
    at com.myCompany.basePackageToScan.SmsQueueConsumer.<init>(SmsQueueConsumer.java:54)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:147)
    ... 45 more

Это та же трассировка стека, которую я получаю, когда запускаю приложение в Tomcat 7. Пожалуйста, дайте мне знать, если есть какие-либо другие подробности, которые мне нужно предоставить.

РЕДАКТИРОВАТЬ --- Я считаю, что проблема может быть связана с тем, как RabbitMq инициирует потребителя... Он ждет сообщений. Возможно, Spring не может Autowire этого класса?

РЕДАКТИРОВАТЬ 2 --- Удаление автоподключения конфигурации и добавление жестко закодированных настроек в SmsQueueConsumer для rabbitMqHost работает... Теперь, почему значения, извлеченные из конфигурации, не работают?


java rabbitmq spring inversion-of-control apache-commons-config
person Matt    schedule 03.10.2015    source источник
comment
Спасибо Тунаки, да, это была опечатка. Я обновил пост.   -  person Matt    schedule 03.10.2015

Ответы (1)


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Хорошо, это немного хакерское ощущение, но вместо того, чтобы использовать конструктор по умолчанию, я добавил класс Configuration в качестве аргумента конструктора.

@Component
public class SmsQueueConsumer {

     //I removed the autowiring of the config
     //@Autowired
     //Configuration config;

    //and placed the config as an arg to the constructor
    public SmsQueueConsumer(Configuration config) throws Exception {

        //THIS IS WHERE THE NULL POINTER OCCURS (stack trace refers to line 54)
        String rabbitMqHost = config.getString("rabbitMq.hostName");

        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost(rabbitMqHost);
        com.rabbitmq.client.Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(queueName, false, false, false, null);

        Consumer consumer = new DefaultConsumer(channel) {

            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties, byte[] body) throws IOException {
             //... handle deliv logic
        };
    }

}

Затем я создал bean-компонент в applicationContext.xml, который внедряет файл Configuration.

<bean id="config" class="org.apache.commons.configuration.PropertiesConfiguration">
    <constructor-arg value = "some.properties"/>
</bean>

<bean id="bidsSmsQueueConsumer" class="com.myCompany.basePackage.SmsQueueConsumer">
    <constructor-arg ref = "config" />
</bean>
person Matt    schedule 03.10.2015