NullPointerException from DAO by using crudRepositoy

[jaiwo99]

Hi,

i got java.lang.NullPointerException by using CrudRepository

my project looks like this:

strut2 action
service
repository
domain

class Action {
  @Autowired MyService service;
  public String execute(){
    service.getList();
    return "ok";
  }
}

interface Service {
  List getList();
}

@org.springframework.stereotype.Service
class ServiceImpl implements Service {
  @Autowired MyRepository repo;
  List getList(){
    return (List)repo.findAll();
  }
}
package com.mycompany.repositories;
interface MyRepository extends CrudRepository<MyPojo, String>{}

here is the applicationContext.xml:

  <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:jpa="http://www.springframework.org/schema/data/jpa"
       xsi:schemaLocation=" http://www.springframework.org/schema/beans 
                            http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
                            http://www.springframework.org/schema/context
                            http://www.springframework.org/schema/context/spring-context-3.1.xsd
                            http://www.springframework.org/schema/tx
                            http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
                            http://www.springframework.org/schema/data/jpa 
                            http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">
    
    <jpa:repositories base-package="com.mycompany.repositories" />
    
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager" >
        <property name="entityManagerFactory" ref="entityManagerFactory" />
        <property name="jpaDialect">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
        </property>
    </bean>
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="persistenceUnitName" value="unit-name" />
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <property name="showSql" value="true" />
                <property name="generateDdl" value="true" />
                <property name="database" value="POSTGRESQL"/>
            </bean>
        </property>
    </bean>
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="username" value="root" />
        <property name="password" value="root" />
        <property name="driverClassName" value="org.postgresql.Driver" />
        <property name="url" value="jdbc:postgresql://127.0.0.1:5432/mydb" />
    </bean>
    
    <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"></bean>  

    <tx:annotation-driven transaction-manager="transactionManager" />
</beans>

I'm new here, and everytime i call the Action class, the service is injected, but MyRepository is alway null.

could someone help me with please, if you need more infos, pls let me know, thx!

[prashob]

define getter method and setter method for repo and then put @Autowired above the setter method and try.

[jaiwo99]

Hi prashob,

thx for your comment! i just tried on my ServiceImpl class to add setter for the repo. It is still not working

public class ServiceImpl implements Server{
  MyRepository repo;
  
  @Autowired
  public void setRepo(MyRepository repo){
    this.repo = repo;
  }
}

[Marten Deinum]

I doubt that the service gets injected and I suspect you are creating your own instance of the service (if @Autowired fails you would get an exception during startup!). In your configuration there is nothing that enables @Autowired or detecting your @Service (no context:component-scan).

Also that Action what kind of class is that and how is that being constructed? If it isn't under spring control nothing is going to be injected...

[jaiwo99]

Hello Marten,

thx for your comment, the Action class is implemented with Struts2, i thought if i got

<jpa:repositories base-package="com.myproject.repositories" />,

i do not have to declare

<context:component-scan base-package="com.myproject.repositories" />.

i am think of that the action classes are not really under control of spring, i am not sure, how it works, maybe i do not need @Service at all, if it is not working.

best, j

[Marten Deinum]

Yuo don't need if for your repositories but for your @Service. Also I suggest you read the spring struts intregration stuff on the struts website. I also suggest the search as the questions regarding struts2 and spring have been answered numerous times before.

[jaiwo99]

Hello Marten,

thx for your comment, did you mean that i only need to declare <jpa:repositories /> and the base-package should point to my package, which contains the @Service. could i may be point the base-package to the parent package like "com.myproject"? because i have two packages for the services "com.myproject.service" for the interfaces and "com.myproject.service.impl" for the implementation.

and Status UPDATE:

i have added struts spring support yesterday, and it works well without @Service, i called MyRepository directly from my struts Action class.

HOW can i add the service tier under control of spring. what kind of configuration do i need.

appreciate your help.

best, j