Java – No bean named ‘…’ is defined and Spring @Resource annotation

javaservletsspringtomcat

I use @Resource to annotate bean classes, @Autowired to autowire dependencies,
and in Spring configuration file these things:

    context:component-scan base-package="package1,package2" 
    tx:annotation-driven

So, it works fine (tested). Spring scans package1, package2, classes with @Resource annotation
and then I can get them using getBean() IF TESTED FROM CONSOLE APPLICATION [say, with main() function].

But when I try to use next approach (to use Spring in container managed environment = with Tomcat):

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath*:beans.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.request.RequestContextListener</listener-class>
    </listener>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

compile a jar with all the bean classes and put this jar into WEB-INF/lib

then what I see? I cannot getBean() any of those @Resource annotated beans!
Spring simply cannot find them.
Still I can getBean() beans that are explicitly present in beans.xml.

Where's the problem?

Best Answer

Is missing <context:annotation-config/>?

<context:annotation-config/>    
<context:component-scan base-package="package1"/>
<context:component-scan base-package="package2"/>
<tx:annotation-driven transaction-manager="transactionManager" />

or 

<context:annotation-config/>    
<context:component-scan base-package="package1, package2"/>
<tx:annotation-driven transaction-manager="transactionManager" />

Related Solutions

Spring – way to @Autowire a bean that requires constructor arguments

You need the @Value annotation.

A common use case is to assign default field values using "#{systemProperties.myProp}" style expressions.

public class SimpleMovieLister {

  private MovieFinder movieFinder;
  private String defaultLocale;

  @Autowired
  public void configure(MovieFinder movieFinder, 
                        @Value("#{ systemProperties['user.region'] }") String defaultLocale) {
      this.movieFinder = movieFinder;
      this.defaultLocale = defaultLocale;
  }

  // ...
}

See: Expression Language > Annotation Configuration

To be more clear: in your scenario, you'd wire two classes, MybeanService and MyConstructorClass, something like this:

@Component
public class MyBeanService implements BeanService{
    @Autowired
    public MybeanService(MyConstructorClass foo){
        // do something with foo
    }
}

@Component
public class MyConstructorClass{
    public MyConstructorClass(@Value("#{some expression here}") String value){
         // do something with value
    }
}

Update: if you need several different instances of MyConstructorClass with different values, you should use Qualifier annotations

Spring autowiring with unique beans: Spring expected single matching bean but found 2

The issue is because you have a bean of type SuggestionService created through @Component annotation and also through the XML config . As explained by JB Nizet, this will lead to the creation of a bean with name 'suggestionService' created via @Component and another with name 'SuggestionService' created through XML .

When you refer SuggestionService by @Autowired, in your controller, Spring autowires "by type" by default and find two beans of type 'SuggestionService'

You could do the following

Remove @Component from your Service and depend on mapping via XML - Easiest
Remove SuggestionService from XML and autowire the dependencies - use util:map to inject the indexSearchers map.

Use @Resource instead of @Autowired to pick the bean by its name .

 @Resource(name="suggestionService")
 private SuggestionService service;

    @Resource(name="SuggestionService")
    private SuggestionService service;

both should work.The third is a dirty fix and it's best to resolve the bean conflict through other ways.

Best Answer

Related Solutions

Spring – way to @Autowire a bean that requires constructor arguments

Spring autowiring with unique beans: Spring expected single matching bean but found 2

Related Topic