Spring + JPA + Hibernate [英] Spring + JPA + Hibernate

问题描述

我在春天是新手。我试图用Spring 3.1.3和JPA 2.0
设置简单的Web应用程序我已经将所有必需的库添加到WEB-INF / lib。启动期间没有错误，但DaoImpl文件中的entityManager为空。
因此，这是我的配置：

persistance.xml

 <？xml version =1.0encoding =UTF-8？> 
< persistence version =2.0
 xmlns =http://java.sun.com/xml/ns/persistencexmlns：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 =fcmsServertransaction-type =RESOURCE_LOCAL> 
< / persistence-unit> 
< /余辉> 
  

fcms-servlet.xml

 <？xml version =1.0encoding =UTF-8？> 
< beans xmlns =http://www.springframework.org/schema/beans
 xmlns：xsi =http://www.w3.org/2001/XMLSchema-instancexmlns ：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\"> 
 
 <！ -  fcmsServer DispatcherServlet的应用程序上下文定义 - > 
 
< bean id =entityManagerFactory
 class =org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean> 
< property name =persistenceUnitNamevalue =fcmsServer/> 
< property name =dataSourceref =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 =showSqlvalue =true/> 
< property name =generateDdlvalue =true/> 
< property name =databasePlatformvalue =org.hibernate.dialect.H2Dialect/> 
< / bean> 
< / property> 
< property name =persistenceUnitManager> 
< bean 
 class =org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager> 
< property name =defaultDataSourceref =dataSource/> 
< / bean> 
< / property> 
< / bean> 
 
< bean id =dataSourceclass =org.apache.commons.dbcp.BasicDataSource
 destroy-method =close> 
< property name =driverClassNamevalue =org.h2.Driver/> 
< property name =urlvalue =jdbc：h2：tcp：// localhost /〜/ fcms/> 
< property name =usernamevalue =sa/> 
< property name =passwordvalue =sa/> 
< / bean> 
 
< tx：注解驱动的事务管理器=transactionManager/> 
< bean id =transactionManagerclass =org.springframework.orm.jpa.JpaTransactionManager> 
< property name =entityManagerFactoryref =entityManagerFactory/> 
< property name =dataSourceref =dataSource/> 
< / bean> 
 
< bean id =persistenceAnnotation
 class =org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor/> 
 
 
< bean id =userDaoclass =fcms.data.user.UserDAOImpl> 
< / bean> 
 
< bean name =/ user.htmclass =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 =prefixvalue =/ WEB-INF / jsp />< / property> 
< property name =suffixvalue =。jsp>< / property> 
< / bean> 
  

DaoImpl class：

  @Repository 
 public class UserDAOImpl implements UserDAO {
 @PersistenceContext（unitName =fcmsServer）
私人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）; 
 
 
 $ / code $ / pre 
 $ b $用户等级
 
 
  @Entity 
 @Table（name =User）
 public class User实现Serializable {
 
 
 @Id @GeneratedValue 
私人长ID; 
 @Column（name =lastName，nullable = false）
 private String lastName; 
 @Column（name =firstName，nullable = false）
 private String firstName; 
 @Column（name =birthDate，nullable = true）
私人日期birthDate; 
 private static final long serialVersionUID = 1L; 
  
 
 
  
} 
 
 
 
当我尝试在UserController中调用addUser（）时，在持久化期间我有NullPointerException。 
解决方案
我认为你错过了配置以告诉spring搜索注释（在< beans> 元素： 
 
 
 < context：annotation-config /> ; 
  
也许您还需要添加以下指定包含DAO的包，但是我
 < context：component-scan base-package =your.package/> ; 
  
 
I am newbie in Spring. I am trying to setup simple web application with Spring 3.1.3 and JPA 2.0
I have added all necessary libs to the WEB-INF/lib. There is no errors during the startup but entityManager in my DaoImpl file is null.
So, this is my configuration:


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() in UserController, I have NullPointerException during persist. 
解决方案
I think you're missing the configuration to tell spring to search for the annotations (add the following anywhere between the <beans> element:
<context:annotation-config />
And maybe you also need to add the following specifying the package where you have the DAO. But I don't think this is required.
<context:component-scan base-package="your.package" />


                        
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