how to inject DAO with Spring???

[gopal kishan]

Hi All,

I am currently working of JSF with Hibernate. And i want to use Spring IOC for my DAO, so that i can avoid the multiple instances of DAO,

actually my framework is

JSF-serviceLayer -DAO(hibernate) - DB
i dont know how to configure those DAO with Spring.

please provide some information.

I want to inject those DAO.

[Michael Duffy]

Originally posted by gopal kishan:
Hi All,

I am currently working of JSF with Hibernate. And i want to use Spring IOC for my DAO, so that i can avoid the multiple instances of DAO,

actually my framework is

JSF-serviceLayer -DAO(hibernate) - DB
i dont know how to configure those DAO with Spring.

please provide some information.

I want to inject those DAO.

Same as injecting any Java object into another:

(1) Create the DAO interface and an implementation using the technology of your choice:

    
public interface FooDAO
{
   public Foo find(long id);
   public List findAll();
   public void saveOrUpdate(Foo foo);
   public void delete(Foo foo);
}

(2) Create a service interface of some kind that will use the DAO:

    
public interface FooService
{
   public void doSomething();
}

(3) Create a service implementation that will use the DAO:

    
public class FooServiceImpl
{
   private FooDAO fooDao;
 
   public void doSomething()
   {
      // use the DAO here
   }
}

(4) Wire it into your Spring context for the service:

    
   <bean id="fooDao" class="FooDAOImpl">
      // FooDAO will need to know about database connection info
   </bean>
 
   <bean id="fooService" class="FooServiceImpl">
      <property name="fooDao"><ref bean="fooDao"/></property>
   </bean>

What's the problem? Any Spring book will show you how to do the wiring.

[Michael Duffy]

Sorry, I forgot to add the setter for the DAO on the service implementation AND I didn't have it extend the interface as needed:

public class FooServiceImpl implements FooService
{
   private FooDAO fooDao;
 
   public void setFooDao(FooDAO newFooDao) { fooDao = newFooDao; }
 
   public void doSomething()
   {
      // code that uses the DAO goes in here.
   }
}

My mistake. Sorry.

[gopal kishan]

hi

how to create spring context file.

it is like applicationcontext.xml???


I want to use spring only to inject DAO , not for other, i am directly calling hibernate session in my DAO.i am not using HibernateTemplate.

I need to use only for injection of my dao...

[gopal kishan]

HI I did the same thing as u mentioned.

i created a applicationContext.xml and i placed my

DAO, Service, Database

mappings. and i defined

setter

in serviceImpl.

when i run it shows NullPointerException?

[Sahil Saxena]

Hi,
I have also the same problem.
Today only I tried using JSF/Sprng/Hibernate but when i use Dao isntance from the service implementation class i also get the Null Pointer Exception.
Below is the method from the LoginServiceImpl class:

private LoginDao loginDao;

public void setLoginDao(LoginDao loginDao)
{
this.loginDao = loginDao;
}

public User login(String username, String password) throws Exception
{
User user = null;
try
{
user = this.loginDao.getUser(username);
...................

The configuration made in the applicationContext.xml is as follows

<!-- Login DAO object: Hibernate implementation -->
<bean id="loginDao" class="com.model.dao.hibernateimpl.LoginDaoHibernateImpl">

<property name="hibernateTemplate"><ref bean="hibernateTemplate"/></property>

</bean>

<!-- User Service Defintion -->
<bean id="loginService" class="com.model.service.impl.LoginServiceImpl">
<property name="loginDao"><ref local="loginDao"/></property>
</bean>

I will be also grateful if anyone figure out where am going wrong.
[ February 02, 2006: Message edited by: Sahil Saxena ]

[sushma sree]

Gopal,

if you look at your applicationContext.xml, you have mentioned the class attribute="LoginDaoHibernateImpl" whereas in your LoginServiceImpl class you have a setter for LoginDao object. So, you have to make sure that the setter in your class matches the class you specified in class attribute. Hope this is helpful. Let me know if i am wrong

[Udaya Raj]

Hi Gopal,

Did you find a solution? I am also facing the same issue?

Regards

Uday