Spring + JPA + Hibernate
I am new to Spring. I am trying to set up a simple web application using Spring 3.1.3 and JPA 2.0 I have added all the required libraries to WEB-INF / lib. There are no errors during startup, but the entityManager in my DaoImpl file is NULL. So this is my config:
persistance.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
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_2_0.xsd">
<persistence-unit name="fcmsServer" transaction-type="RESOURCE_LOCAL">
</persistence-unit>
</persistence>
FCMS-servlet.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"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd">
<!-- the application context definition for the fcmsServer DispatcherServlet -->
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceUnitName" value="fcmsServer" />
<property name="dataSource" ref="dataSource" />
<property name="jpaDialect">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
</property>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="showSql" value="true" />
<property name="generateDdl" value="true" />
<property name="databasePlatform" value="org.hibernate.dialect.H2Dialect" />
</bean>
</property>
<property name="persistenceUnitManager">
<bean
class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager">
<property name="defaultDataSource" ref="dataSource" />
</bean>
</property>
</bean>
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" value="org.h2.Driver" />
<property name="url" value="jdbc:h2:tcp://localhost/~/fcms" />
<property name="username" value="sa" />
<property name="password" value="sa" />
</bean>
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
<property name="dataSource" ref="dataSource" />
</bean>
<bean id="persistenceAnnotation"
class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />
<bean id="userDao" class="fcms.data.user.UserDAOImpl">
</bean>
<bean name="/user.htm" class="fcms.controller.UserController">
</bean>
<bean id="viewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass"
value="org.springframework.web.servlet.view.JstlView"></property>
<property name="prefix" value="/WEB-INF/jsp/"></property>
<property name="suffix" value=".jsp"></property>
</bean>
DaoImpl class:
@Repository
public class UserDAOImpl implements UserDAO {
@PersistenceContext(unitName = "fcmsServer")
private EntityManager entityManager;
public void setEntityManager(EntityManager entityManager) {
this.entityManager = entityManager;
}
@Override
public User getUserById(long id) {
return entityManager.find(User.class,id);
}
@Override
public void addUser(User u) {
entityManager.persist(u);
}
}
User class
@Entity
@Table(name = "User")
public class User implements Serializable {
@Id @GeneratedValue
private long id;
@Column(name = "lastName", nullable = false)
private String lastName;
@Column(name = "firstName", nullable = false)
private String firstName;
@Column(name = "birthDate", nullable = true)
private Date birthDate;
private static final long serialVersionUID = 1L;
}
So when I try to call addUser () on the UserController, I have a NullPointerException during save.
source to share
I think you are missing the configuration to tell spring to look for annotations (add the following somewhere between the element <beans>
:
<context:annotation-config />
And maybe you need to add the following as well, specifying the package where you have the DAO. But I don't think this is required.
<context:component-scan base-package="your.package" />
source to share
this is a working piece of code:
Spring.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: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.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">
<context:annotation-config />
<context:component-scan base-package="com.package.dao" />
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
<property name="persistenceUnitName" value="fcmsServer" />
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
</beans>
Tao bean:
@Repository
public class UserDaoBean implements UserDao {
@PersistenceContext
protected EntityManager em;
}
persistence.xml:
<?xml version="1.0" encoding="UTF-8" ?>
<persistence 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"
version="1.0">
<persistence-unit name="fcmsServer" transaction-type="RESOURCE_LOCAL">
<class>com.package.entity.</class>
<properties>
<property name="javax.persistence.jdbc.url"
value="jdbc:mysql://localhost:3306/db_name"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.user" value="admin"/>
<property name="javax.persistence.jdbc.password" value="admin"/>
</properties>
</persistence-unit>
</persistence>
source to share