java - Can spring @Autowired Map?

Question

Here's the Map

@Autowired
private Map<String, ISendableConverter> converters;

and ISendableConverter

public interface ISendableConverter {

    ISendableMsg convert(BaseMessage baseMessage);

    String getType();
}

There are some classes that implements ISendableConverter

I want to inject them into the variable converters by using spring @Autowried annotation.

The instance of class as value, and the result of method getType() as key.

like this one

@Component
public class SendableVoiceMsgConverter implements ISendableConverter {

    @Override
    public ISendableMsg convert(BaseMessage baseMessage) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public String getType() {
        return "VOICE";
    }
}

Is this possible? and how?

Answer 1

Try with something like @Resource - I have not tested this code.

@Resource(name="converters")
private Map<String, ISendableConverter> converters;

or

@Value("#{converters}")
private Map<String, ISendableConverter> converters;

From Spring Docs

(..) beans that are themselves defined as a collection or map type cannot be injected through @Autowired, because type matching is not properly applicable to them. Use @Resource for such beans, referring to the specific collection or map bean by unique name.

This should work, only if you prepare converters bean like this:

<util:map id="converters" scope="prototype" map-class="java.util.HashMap" 
          key-type="java.lang.String" value-type="...ISendableConverter">
    <entry key="VOICE" value="sendableVoiceMsgConverter" />
</util:map>

This is also similar question:

• Auto-wiring a List using util schema gives NoSuchBeanDefinitionException
• Spring can't autowire Map bean