Spring：整合JPA

  

<context:annotation-config/>

    <bean id="entityManagerFactory" class="org.springframework.orm.jpa. LocalEntityManagerFactoryBean">
      <property name="persistenceUnitName" value="itcast"/>
    </bean>
    <bean id="txManager" class="org.springframework.orm.jpa. JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
   </bean>

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

META-INF下的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="itcast" transaction-type="RESOURCE_LOCAL">
      <properties>
         <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
         <property name="hibernate.connection.driver_class" value="org.gjt.mm.mysql.Driver"/>
         <property name="hibernate.connection.username" value="root"/>
         <property name="hibernate.connection.password" value="123456"/>
         <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/itcast?useUnicode=true&amp;characterEncoding=UTF-8"/>
         <property name="hibernate.max_fetch_depth" value="3"/>
         <property name="hibernate.hbm2ddl.auto" value="update"/>
      </properties>
  </persistence-unit>
</persistence>

bean的定义

@Entity
public class Person implements Serializable{
    private Integer id;
    private String name;
    
    public Person(){}
    
    public Person(String name){
        this.name = name;
    }
    
    @Id @GeneratedValue
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    @Column(length=10,nullable=false)
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((id == null) ? 0 : id.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        final Person other = (Person) obj;
        if (id == null) {
            if (other.id != null)
                return false;
        } else if (!id.equals(other.id))
            return false;
        return true;
    }
    
}

service中

@Transactional

@Service
public class PersonServiceBean implements PersonService {
    @PersistenceContext EntityManager em;
    
    public void save(Person person){
        em.persist(person);
    }
    
    public void update(Person person){
        em.merge(person);
    }
    
    public void delete(Integer personid){
        em.remove(em.getReference(Person.class, personid));
    }
    @Transactional(propagation=Propagation.NOT_SUPPORTED,readOnly=true)
    public Person getPerson(Integer personid){
        return em.find(Person.class, personid);
    }
    @Transactional(propagation=Propagation.NOT_SUPPORTED,readOnly=true)
    @SuppressWarnings("unchecked")
    public List<Person> getPersons(){
        return em.createQuery("select o from Person o").getResultList();
    }
}

在web.xml中使用过滤器解决延迟加载的问题

<filter>
            <filter-name>Spring OpenEntityManagerInViewFilter</filter-name>
            <filter-class>org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter</filter-class>
     </filter>
     <filter-mapping>
            <filter-name>Spring OpenEntityManagerInViewFilter</filter-name>
            <url-pattern>/*</url-pattern>
     </filter-mapping>