@Autowired and static method

Question

I have @Autowired service which has to be used from within a static method. I know this is wrong but I cannot change the current design as it would require a lot of work, so I need some simple hack for that. I can't change randomMethod() to be non-static and I need to use this autowired bean. Any clues how to do that?

@Service
public class Foo {
    public int doStuff() {
        return 1;
    }
}

public class Boo {
    @Autowired
    Foo foo;

    public static void randomMethod() {
         foo.doStuff();
    }
}

Answer 1

You can do this by following one of the solutions:

Using constructor @Autowired

This approach will construct the bean requiring some beans as constructor parameters. Within the constructor code you set the static field with the value got as parameter for constructor execution. Sample:

@Component
public class Boo {

    private static Foo foo;

    @Autowired
    public Boo(Foo foo) {
        Boo.foo = foo;
    }

    public static void randomMethod() {
         foo.doStuff();
    }
}

Using @PostConstruct to hand value over to static field

The idea here is to hand over a bean to a static field after bean is configured by spring.

@Component
public class Boo {

    private static Foo foo;
    @Autowired
    private Foo tFoo;

    @PostConstruct
    public void init() {
        Boo.foo = tFoo;
    }

    public static void randomMethod() {
         foo.doStuff();
    }
}

Answer 2

You have to workaround this via static application context accessor approach:

@Component
public class StaticContextAccessor {

    private static StaticContextAccessor instance;

    @Autowired
    private ApplicationContext applicationContext;

    @PostConstruct
    public void registerInstance() {
        instance = this;
    }

    public static <T> T getBean(Class<T> clazz) {
        return instance.applicationContext.getBean(clazz);
    }

}

Then you can access bean instances in a static manner.

public class Boo {

    public static void randomMethod() {
         StaticContextAccessor.getBean(Foo.class).doStuff();
    }

}