Not able to wire entityManager with applicationContext bean - spring-mvc

Question

I am facing a problem to wire entity manager with the bean present in application context.
whenever i do some operation it gives NullPointerException.
this is my applicationContext.xml file
<?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:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<context:component-scan base-package="com.ajit.retail"/>
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.postgresql.Driver"/>
<property name="url" value="jdbc:postgresql://localhost/retail"/>
<property name="username" value="retail_user"/>
<property name="password" value="password"/>
</bean>
<bean id="entityManagerOne" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="showSql" value="true"/>
<property name="databasePlatform" value="org.hibernate.dialect.PostgreSQL82Dialect"/>
</bean>
</property>
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerOne"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
</beans>
this is the java file in which i am creating the entity manager
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
public class AbstractRepository {
#PersistenceContext
EntityManager entityManager;
}
so whenever i use this entity manager it gives null pointer exception
please help!

Answer 1

Your entity manager bean is called enetityManagerOne, but the variable is called entityManager. Maybe renamme your bean in your XML file:
<bean id="entityManager" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
Another solution could be you forgot the following bean declarations:
For the support for transaction:
<tx:annotation-driven/>
The support for parsing JPA annotations:
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/>

Answer 2

my application context was not on the correct place (src/main/resources). Now I put that there and its working.

Answer 3

Use this code in your dispatcher-servlet.xml
<bean id="persistenceUnitManager" class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager">
<property name="persistenceXmlLocations">
<list>
<value>classpath*:META-INF/persistence.xml</value>
</list>
</property>
<property name="defaultDataSource" ref="dataSource"/>
</bean>
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceUnitManager" ref="persistenceUnitManager"/>
<property name="persistenceUnitName" value="etray"/>
</bean>
<jee:jndi-lookup id="dataSource" jndi-name="java:/prateek" />
<!-- we plan to use JTA transactions and declare them using annotations -->
<bean id="transactionManager"
class="org.springframework.transaction.jta.JtaTransactionManager" />
<tx:annotation-driven transaction-manager="transactionManager" />
<!-- to inject instances of EntityManager using #PersistenceContext annotation -->
<bean
class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />
it resolve my problem, hope it will help.