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javaspringdependency-injectionannotationsautowired

@Resource vs @Autowired

Which annotation, @Resource (jsr250) or @Autowired (Spring-specific) should I use in DI?

I have successfully used both in the past, @Resource(name="blah") and @Autowired @Qualifier("blah")

My instinct is to stick with the @Resource tag since it's been ratified by the jsr people.
Anyone has strong thoughts on this?

Solution

  • In spring pre-3.0 it doesn't matter which one.

    In spring 3.0 there's support for the standard (JSR-330) annotation @javax.inject.Inject - use it, with a combination of @Qualifier. Note that spring now also supports the @javax.inject.Qualifier meta-annotation:

    @Qualifier
@Retention(RUNTIME)
public @interface YourQualifier {}

    So you can have

    <bean class="com.pkg.SomeBean">
   <qualifier type="YourQualifier"/>
</bean>

    or

    @YourQualifier
@Component
public class SomeBean implements Foo { .. }

    And then:

    @Inject @YourQualifier private Foo foo;

    This makes less use of String-names, which can be misspelled and are harder to maintain.

    As for the original question: both, without specifying any attributes of the annotation, perform injection by type. The difference is:

    • @Resource allows you to specify a name of the injected bean
    • @Autowired allows you to mark it as non-mandatory.