I'm trying to use JPA with hibernate entity manager in my application, but every time I invoke any method on an entity manager bean, I get a nullpointerexception.
Here's my applicationContext.xml:
persistence.xml:Code:<?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" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation=" http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <property name="driverClassName" value="com.mysql.jdbc.Driver" /> <property name="url" value="jdbc:mysql://localhost:3306/bugs" /> <property name="username" value="bugs" /> <property name="password" value="bugs/> </bean> <bean id="emf" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="persistenceUnitName" value="bugsUnit" /> <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="MYSQL" /> </bean> </property> </bean> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="emf" /> </bean> <bean id="entityController" class="org.bugs.controller.EntityController" scope="session"/> <bean id="user" class="org.bugs.session.User" scope="session"> <property name="controller" ref="entityController"/> </bean> <tx:annotation-driven /> </beans>
EntityController.java:Code:<?xml version="1.0" encoding="UTF-8"?> <persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"> <persistence-unit name="bugsUnit" transaction-type="RESOURCE_LOCAL"> <provider>org.hibernate.ejb.HibernatePersistence</provider> </persistence-unit> </persistence>
User.java:Code:package org.bugs.controller; import java.util.List; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import org.springframework.transaction.annotation.Transactional; public class EntityController { @PersistenceContext private EntityManager em; @SuppressWarnings("unchecked") @Transactional public <T> List<T> getList(Class<T> clase){ return em.createQuery("select p from "+clase.getSimpleName()+" p").getResultList(); } @Transactional public void save(Object objeto){ em.persist(objeto); } @Transactional public void delete(Object objeto){ em.remove(objeto); } }
Anytime I invoke the saveEntity method, I get a NullPointerException in the controller.save(entity) line.Code:package org.bugs.session; import java.util.Date; ... public class User { private EntityController controller; ... public void setController(EntityController controller) { this.controller= controller; } public EntityController getController() { return controller; } public void saveEntity() { MyEntity entity = new MyEntity(); ... controller.save(entity); } ... }
I'm new to Spring and JPA so I must have made a mistake somewhere.
Anybody can help me?


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