@Autowired and @Service working from controller but not from a different package

Question

I need help understanding the concept behind @Autowired and @Service. I have a DAO defined with @Service and controller with @Autowired and everything seems fine, however, I use the same @Autowired in a different class then it does not work.

Example:

Service

@Service
public class MyService {
    private JdbcTemplate jdbcTemplate;

    @Autowired
    public void setDataSource (DataSource myDataSource) {
        this.jdbcTemplate = new JdbcTemplate(myDataSource);
    } 

    public void testUpdate(){
            jdbcTemplate.update("some query");
    }
}

Controller

package com.springtest.mywork.controller;

@Controller
@RequestMapping(value = "/test.html")
public class MyController
{
  @Autowired
  MyService myService;

  @RequestMapping(method = RequestMethod.GET)
  public String test(Model model)
  {
    systemsService.testUpdate();
    return "view/test";
  }
}

The above all works fine. However, If I want to use MyService in a POJO then it just doesn't work. Example:

package com.springtest.mywork.pojos;
public class MyPojo {

    @Autowired
    MyService myService;

    public void testFromPojo () {
        myService.someDataAccessMethod(); //myService is still null
    }
}

Spring Config:

<beans>
    <mvc:annotation-driven />
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
    <context:component-scan base-package="com.springtest.mywork" />
    <bean id="dataSource" destroy-method="close" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/mydb" />
        <property name="username" value="hello" />
        <property name="password" value="what" />
    </bean>

    <bean name="jdbcTemplate" class="org.springframework.jdbc.core.simple.SimpleJdbcTemplate">
        <constructor-arg ref="dataSource"/>
    </bean>
 </beans>

I have not done anything for `MyController` in config.xml so i didn't do it for `MyPojo` either. What should I be doing? — birdy, Oct 12 '12 at 15:23

score 16 · Accepted Answer · edited Jan 15 '22 at 19:59

It is because your POJO class is not managed by spring container.

@Autowire annotation will work only those objects which are managed by spring (ie created by the spring container).

In your case the service and controller object are managed by spring, but your POJO class is not managed by spring, that is why the @Autowire is not producing the behavior expected by you.

Another problem I noticed is, you are using the @Service annotation in the DAO layer when spring has the @Repository annotation specifically created for this purpose.

Also it is not desirable to allow spring to manage the POJO classes since normally it will be data storage elements which has to be created outside the container.

let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/17940/discussion-between-arun-p-johny-and-birdy) — Arun P Johny, Oct 12 '12 at 16:07

David Grant · Answer 2 · 2012-10-12T15:39:55.067

5

When using classpath scanning, you have to communicate to Spring which classes to manage. This is done using the @Service annotation, and its relations (@Controller, @Repository, etc).

If you choose not to annotate your bean, you must explicitly declare it in your config, just like you did with dataSource and jdbcTemplate.

Annotating your classes means only those classes in the package are managed by Spring; which allows you to scan a package without having to manage all classes in that package.

edited Oct 12 '12 at 15:39

answered Oct 12 '12 at 15:32

David Grant

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So I should annotate my POJO with `@Service` or `@Repository` or `@Controller`? – birdy Oct 12 '12 at 15:34
I would prefer to add annotation rather than define it in the xml – birdy Oct 12 '12 at 15:36
"Annotating your classes prevents every class in a package being managed by Spring; something that isn't often desirable." really? so in a package only one class can be annotated? – birdy Oct 12 '12 at 15:37
`@Service` is the most non-specific, so that's what I'd use. – David Grant Oct 12 '12 at 15:38
@birdy I mean, by annotating, you choose which classes to be managed. – David Grant Oct 12 '12 at 15:38
even with @Service it is coming to NULL :( – birdy Oct 12 '12 at 15:41
And it's in the same package? – David Grant Oct 12 '12 at 15:42
no. Its in a different package. Controller is in `com.springtest.mywork.controller` and pojo is in `com.springtest.mywork.mypojo` . In the spring config I have `` so I'm assuming both sub packages `controller` and `mypojo` should be scanned...? – birdy Oct 12 '12 at 15:44
Try adding `` (as @Pradeep mentions below) – David Grant Oct 12 '12 at 15:49
still same. I give up. perhaps i need to step away – birdy Oct 12 '12 at 15:52

score 2 · Answer 3 · answered Oct 12 '12 at 15:32

2

Include this in applicationContext.xml file

<context:annotation-config />

answered Oct 12 '12 at 15:32

NPKR

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score 0 · Answer 4 · answered Oct 08 '15 at 08:09

0

You can implement this to use spring-managed beans in your POJO class.

http://www.javacodegeeks.com/2015/03/using-spring-managed-bean-in-non-managed-object.html

answered Oct 08 '15 at 08:09

Hazim

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1

Please avoid link only answers. – Maciej Lach Oct 08 '15 at 08:26

score -1 · Answer 5 · answered Oct 12 '12 at 15:22

-1

check your context component scan in your configuration file

<context:component-scan base-package="<your_package>" />

answered Oct 12 '12 at 15:22

phury

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I've checked this. It is scanning all the packages. – birdy Oct 12 '12 at 15:24

@Autowired and @Service working from controller but not from a different package

5 Answers5

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