如何在Spring类中使用注释注入JmsTemplate对象？

Question

I am trying to inject a JmsTemplate object into a class using @Autowired , but it is giving a NullPointerException whenever I try to send messages. While in the application class I could instantiate jmsTemplate using the ApplicationContext

ConfigurableApplicationContext context = SpringApplication.run(Application.class, args);
JmsTemplate jmsTemplate = context.getBean(JmsTemplate.class);

I could not do this in any other class, as I did not figure out how to get the context object.

This is my application class:

@EnableAutoConfiguration
public class Application {

  private static final String maxFileSize = "512KB";
  private static final String maxRequestSize = "512KB";

  static String IncomingMailboxDestination = "Responses";

  @Bean
  Receiver receiver() {
    return new Receiver();
  }

  @Bean
  Producer producer() {
    return new Producer();
  }

  @Bean
  MessageListenerAdapter adapter(Receiver receiver) {
    MessageListenerAdapter messageListener
            = new MessageListenerAdapter(receiver);
    messageListener.setDefaultListenerMethod("receiveMessage");
    return messageListener;
  }

  @Bean
  SimpleMessageListenerContainer container(MessageListenerAdapter messageListener,
                                         ConnectionFactory connectionFactory) {
    SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
    container.setMessageListener(messageListener);
    container.setConnectionFactory(connectionFactory);
    container.setDestinationName(IncomingMailboxDestination);
    return container;
   }

  @Bean
  MultipartConfigElement multipartConfigElement() {
    MultipartConfigFactory factory = new MultipartConfigFactory();
    factory.setMaxFileSize(maxFileSize);
    factory.setMaxRequestSize(maxRequestSize);
    return factory.createMultipartConfig();
  }

  public static void main(String[] args) {
     // Clean out any ActiveMQ data from a previous run
    FileSystemUtils.deleteRecursively(new File("activemq-data"));

    // Launch the application
    ConfigurableApplicationContext context = SpringApplication.run(Application.class, args);


}
}

and this is the Producer class:

@Component("producer")
public class Producer 
{
  @Autowired   
  @Qualifier("jmsTemplate")
  private JmsTemplate jmsTemplate;
  private static final Logger logger = Logger.getLogger(Producer.class);


  public void convertAndSendMessage(String destination, Message notification) 
  {
    logger.info("sending message : " + notification.getMessage());
    jmsTemplate.convertAndSend(destination, notification);
  }
}

This is the full stack trace:

java.lang.NullPointerException: null
at ncl.jms.Producer.convertAndSendMessage(Producer.java:35)
at ncl.controllers.ModelController.process(ModelController.java:196)
at ncl.controllers.ModelController.process(ModelController.java:202)
at ncl.controllers.ModelController.runModel(ModelController.java:147)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:749)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:689)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:683)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1720)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1679)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:722)

What am I missing here?

Answer 1

passing the jmsTemplate object from the calling class to he convert and send message in my Producer class has worked. But still don't know why it did not work when I try to instantiate it in the Producer class.