传智播客 EJB3 学习笔记2

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