Spring Autowire Bean with multiple Interface Implementations, define Implementation in method

Question

I am new to spring and spring boot, so hopefully it is not a silly question.

I have an interface with several implementations. Implementations are annotated with @Component("NameOfImpl").

My goal is to autowire a bean with selected implementation. In a normal case I can do it with @Autowired @Qualifier("NameOfImpl"), but my Problem is I want to select an Implementation in a method like:

public void doSomethingMethod(){ 
      for(String line: configFile){
                String[] values = line.split(";");

                if (values[0].equals("A")) {
                    //here I want to select an bean implementation

                }
                else if (values[0].equals("B")) {
                    //here I want to select another bean implementation

                }
      }
      bean.doSomething();
    }

How can I achieve that? What do you suggest? Thank you!

you can remove the autowiring since you are instantiating the implementations manually — Rafik BELDI, Nov 30 '15 at 10:28
Yes, I know, I need something instead of using new Impl(); I edit the post — user3287019, Nov 30 '15 at 10:32
take a look at this approach http://stackoverflow.com/questions/15284851/spring-3-dynamic-autowiring-at-runtime-based-on-another-object-attribute — Rafik BELDI, Nov 30 '15 at 10:40

score 11 · Answer 1 · answered Nov 30 '15 at 11:10

You can ask Spring to inject a Map of beans. The keys in the map will be the beans' names.

If you have an interface named Example

public interface Example {

}

And two implementations:

@Component("foo")
public class FooExample implements Example {

}

@Component("bar")
public class BarExample implements Example {

}

You can have a map of Example beans injected:

@Component
public class ExampleConsumer {

    private final Map<String, Example> examples;

    @Autowired
    public ExampleConsumer(Map<String, Example> examples) {
        this.examples = examples;
    }
}

In this case the map will contain two entries:

"foo" -> FooExample instance
"bar" -> BarExample instance

score 0 · Answer 2 · answered Dec 19 '18 at 09:08

This is also working

public interface Example {

}

@Component("foo")
public class FooExample implements Example {

}

@Component("bar")
public class BarExample implements Example {

}

You can simply Auto wire them

@Component
public class ExampleConsumer {

 @Autowired
    private final Map<String, Example> examples;


}

"foo" -> FooExample instance "bar" -> BarExample instance

Spring Autowire Bean with multiple Interface Implementations, define Implementation in method

2 Answers2

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