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

User · Answer

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();
    }

}

User · Answer

Use AppContext  Make sure you create a bean in your context file   private final static Foo foo   AppContext getApplicationContext   getBean Foo class    public static void randomMethod          foo doStuff

User · Answer

What you can do is  Autowired a setter method and have it set a new static field   public class Boo        Autowired     Foo foo       static Foo staticFoo           Autowired     public void setStaticFoo Foo foo            Boo staticFoo   foo             public static void randomMethod              staticFoo doStuff              When the bean gets processed  Spring will inject a Foo implementation instance into the instance field foo  It will then also inject the same Foo instance into the setStaticFoo   argument list  which will be used to set the static field    This is a terrible workaround and will fail if you try to use randomMethod   before Spring has processed an instance of Boo

User · Answer

This builds upon  Pavel s answer  to solve the possibility of Spring context not being initialized when accessing from the static getBean method    Component public class Spring     private static final Logger LOG   LoggerFactory getLogger  Spring class      private static Spring spring      Autowired   private ApplicationContext context      PostConstruct   public void registerInstance          spring   this         private Spring  ApplicationContext context        this context   context         private static synchronized void initContext          if  spring    null          LOG info   Initializing Spring Context             ApplicationContext context   new AnnotationConfigApplicationContext  io zeniq spring BaseConfig class         spring   new Spring  context                public static  lt T gt  T getBean String name  Class lt T gt  className  throws BeansException       initContext        return spring context getBean name  className          public static  lt T gt  T getBean Class lt T gt  className  throws BeansException       initContext        return spring context getBean className          public static AutowireCapableBeanFactory getBeanFactory   throws IllegalStateException       initContext        return spring context getAutowireCapableBeanFactory             The important piece here is the initContext method  It ensures that the context will always get initialized  But  do note that initContext will be a point of contention in your code as it is synchronized  If your application is heavily parallelized  for eg  the backend of a high traffic site   this might not be a good solution for you

User · Answer

It sucks but you can get the bean by using the ApplicationContextAware interface  Something like    public class Boo implements ApplicationContextAware        private static ApplicationContext appContext        Autowired     Foo foo       public static void randomMethod              Foo fooInstance   appContext getBean Foo class            fooInstance doStuff                Override     public void setApplicationContext ApplicationContext appContext            Boo appContext   appContext

User · Answer

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

[java] @Autowired and static method

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