ejb3学习笔记4

1数据源： 详细定义

    <jndi-name>MSSQLDS</jndi-name>
    <connection-url>jdbc:sqlserver://localhost:1433;DatabaseName=EJB</connection-url>
    <driver-class>com.microsoft.sqlserver.jdbc.SQLServerDriver</driver-class>
    <user-name>sa</user-name>
    <password>123456</password>

 

2 配置实体bean

 

@SuppressWarnings("serial")
@Entity
 @Table(name="person")
 public class Person implements Serializable{

     private Integer id;
     private String name;

     public Person(){
    }

     public Person(String name){
         this.name = name;
    }

     @Id @Column(name="id") @GeneratedValue(strategy=GenerationType.IDENTITY)
     public Integer getId() {
         return id;
    }
     public void setId(Integer id) {
         this.id = id;
    }

     @Column(name="name", length=20, 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;
    }

}

  

 

 

3 在jar META-INF 创建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="JTA">
        <jta-data-source>java:MSSQLDS</jta-data-source>
        <properties>
             <property name="hibernate.hbm2ddl.auto" value="update"/>
             <property name="hibernate.show_sql" value="true"/>
             <property name="hibernate.format_sql" value="true"/>
        </properties>
    </persistence-unit>
</persistence>

  

4 dao

 

@Stateless
 @Remote(PersonService.class)
 public class PersonServiceBean implements PersonService{
     @PersistenceContext(unitName="itcast") EntityManager em;

     public void delete(Integer personId) {
         em.remove(em.getReference(Person.class, personId));
         //返回而 代理对象
    }

     public Person getPerson(Integer personId) {
         return em.find(Person.class, personId);
    }

     @SuppressWarnings("unchecked")
     public List<Person> getPersons() {
         return (List<Person>) em.createQuery(" select p from Person p ").getResultList();
    }

     public void save(Person person) {
        em.persist(person);
    }

     public void update(Person person) {
        em.merge(person);
    }
}

 

在dao 中：

@PersistenceContext(unitName="foshanshop") protected EntityManager em;

 

属性：

@Transient 实体bean默认全体成员都会持久， 该注释表示不持久某项

@Enumerated(EnumType.STRING)

public CommentType getType(){

}

 

public enum CommentType{

     NEWS{public String getName(){reutrn "新闻"；}},

     PRODUCT{public String getName(){reutrn "产品"；}}；

     public abstract String getName();

}

 

@Lob 映射Blob  Clob

@Basic(fetch=FetchType.LAZY) 加在lob大文件时 延迟加载

@Temporal 指定时间类型

@Embedded