Spring：整合JPA

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<context:annotation-config/>

<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&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>

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