@Value returning null

Question

I have a couple @Value annotations within my Entity Class. I am not sure why but they are both returning null. I also have "ShaPasswordEncoder" Object Autowired, which too is throwing a NullPointer Exception. I have no idea why. Please advise.

@Repository

@Configurable
@Entity
@Table(name="user")
@NamedQueries({...})
public class User implements Serializable{

    @Transient private static final Logger logger = Logger.getLogger(User.class);
    @Transient private static final AppUtil appUtil = new AppUtil();
    @Transient @Value("some value") private String extDir;
    @Transient @Value("100x100") private String imageSize;
    @Transient private static byte[] salt = "FBar".getBytes();
    @Transient @Autowired private ShaPasswordEncoder passwordEncoder;

....
//Default Constructor
    public User(){
        logger.info("TEST IMAGE => "+imageSize);


    }

    public String passwordEncoder(String password) {
        return passwordEncoder.encodePassword(password,salt);
    }

You really shouldn't be using simple SHA to hash passwords. Look into something like Blowfish. — tereško
– tereško, Commented Jul 29, 2013 at 14:13

Ammar · Accepted Answer · 2013-07-29 14:44:47Z

1

Making a JPA entity as a Spring bean is a bad design. You should keep your entity simple: only getters and setters.

// Only JPA annotations
@Entity
@Table(name="user")
@NamedQueries({...})
public class User {
    // Getters & Setters
}

Then you should delegate the business logic to service classes:

@Service
public class UserService {

    @Autowired
    private ShaPasswordEncoder passwordEncoder;

    @Value("${conf.extDir}")
    private String dir;

   // Some operations ...

   public void createUser(User user) {
       // ...
   }

   public void updateUser(User user) {
       // ...
   }
}

answered Jul 29, 2013 at 14:44

Ammar

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1 Comment

James White Over a year ago

Does anyone else agree with this? I always thought business logic should go in the Model, which this case would be @Entity (User Class)?

maverick · Accepted Answer · 2013-07-29 14:36:36Z

0

Are you passing valid value expressions? For properties placeholder you can use something like:

@Value("${directory.extDirectory}")

You can also use Spring EL and get all the goodness from it using the #{value} check the docs here

Is also possible to assign a default value in case the property is not found

@Value("${directory.extDirectory:defaultValue}")

answered Jul 29, 2013 at 14:36

maverick

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1 Comment

James White Over a year ago

I intend to get the values from propertiez file once I managed to get the explicitly defined value to work. I doubt by replacing the above with a reference to a .properties file will solve it.

Ammar · Accepted Answer · 2013-07-29 14:56:25Z

0

Using Spring annotations on a POJO means you are delegating the creation and the configuration of this bean to the Spring IoC Container !!! The Spring container will supply all the required dependencies.

For example:

@Component
public class MyBean {
    @Value("${data}")
    private String data;

    @Autowired
    private MyService service;

    // ...

}

When you try to instantiate a bean using the new operator, you will get null values.

MyBean bean = new MyBean();

In order to have a fully-configured bean you MUST get it from the applicationContext. The Spring container will provide all the requested dependencies.

MyBean bean = (MyBean) applicationContext.getBean(MyBean.class);

Or

@Component
public class AnotherBean {

    // You are sure that Spring will create and inject the bean for you.
    @Autowired
    private MyBean bean;
}

answered Jul 29, 2013 at 14:56

Ammar

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2 Comments

Ammar Over a year ago

You must enable components auto-detecting: <context:component-scan base-package="org.mycompany" />

James White Over a year ago

I have. Besides I am tempted go with your other suggestion i.e. move the business logic to service layer.

Alireza Fattahi · Accepted Answer · 2013-11-19 20:41:05Z

0

Although the bean is managed by Spring it is also possible that you make a new bean yourself instead of getting it from spring container.

So below code will make a new user but it is not get from Spring context.

User user = new User()

If you use above code the @value is not applied to your bean.

If you want you must get the User from Spring by @Autowired

public class SampleService{

@Autowired
private User user;

public void Sample(){
user.getExtDir(); //here user.extDir is not null

}

}

answered Nov 19, 2013 at 20:41

Alireza Fattahi

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