CODEWITHSUNDEEP
javaspringjavabeansautowired
sergionni
sergionni

Reputation: 13510

Spring:autowired field is null

I need to wire external lib class to my bean,in order to use it as singleton.
.xml config:

<bean id="myBean" class="com.my.MyBean">
 <property name="someLib" value="com.ExternalBean" />
</bean>

java bean:

@Service
public class MyBean {

    @Autowired
    private ExternalBean externalBean;


    public void setExternalBean(ExternalBean externalBean) {
        this.externalBean = externalBean;
    }

Further I use wired variable externalBean in public method ,in order not to instantiate it in every method call. Problem is it null.

Do I wire bean correctly?What is mistake.

Upvotes: 2

Views: 6276

Answers (3)

danny.lesnik
danny.lesnik

Reputation: 18639

I think that the better ide ais to use context path scan:

<context:component-scan base-package="some.external.package">
</context:component-scan>

Make sure that all these classes are within the package. Then mark both classes with one of the Annotations (@Repository, @Service, @Component).

One of the benefits, no setter required.

P.S: If you re using scan base you don't need to declare class as bean, annotations are enough

Upvotes: 1

Ralph
Ralph

Reputation: 120791

loodakrawa is right. A second thing that can cause a problem is, that you have a xml bean declaration for myBean and additional annotated the bean with @Service. I guess this will cause trouble as soon as use enable component scan.

Upvotes: 1

loodakrawa
loodakrawa

Reputation: 1574

You have to define the external class as a bean in order to make @Autowired work.

<bean id="externalBean" class="some.external.package.ExternalBean">
</bean>

<bean id="myBean" class="com.my.MyBean">
</bean>

Also, if you use @Autowired you don't need the setter for it.

Upvotes: 5

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