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>

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2 配置实体bean

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1. @SuppressWarnings("serial")??@Entity??
2. @Table(name="person")?? public?class?Person?implements?Serializable{??
3. ??????????private?Integer?id;??
4. ????private?String?name;?? ??????
5. ????public?Person(){?? ????}??
6. ??????????public?Person(String?name){??
7. ????????this.name?=?name;?? ????}??
8. ??????????@Id?@Column(name="id")?@GeneratedValue(strategy=GenerationType.IDENTITY)??
9. ????public?Integer?getId()?{?? ????????return?id;??
10. ????}??????public?void?setId(Integer?id)?{??
11. ????????this.id?=?id;?? ????}??
12. ??????????@Column(name="name",?length=20,?nullable=false)??
13. ????public?String?getName()?{?? ????????return?name;??
14. ????}??????public?void?setName(String?name)?{??
15. ????????this.name?=?name;?? ????}??
16. ??????????@Override??
17. ????public?int?hashCode()?{?? ????????final?int?prime?=?31;??
18. ????????int?result?=?1;?? ????????result?=?prime?*?result?+?((id?==?null)???0?:?id.hashCode());??
19. ????????return?result;?? ????}??
20. ????@Override??????public?boolean?equals(Object?obj)?{??
21. ????????if?(this?==?obj)?? ????????????return?true;??
22. ????????if?(obj?==?null)?? ????????????return?false;??
23. ????????if?(getClass()?!=?obj.getClass())?? ????????????return?false;??
24. ????????final?Person?other?=?(Person)?obj;??????????if?(id?==?null)?{??
25. ????????????if?(other.id?!=?null)?? ????????????????return?false;??
26. ????????}?else?if?(!id.equals(other.id))?? ????????????return?false;??
27. ????????return?true;?? ????}??
28. ??????}??

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3 在jar META-INF 创建persistence.xml

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1. <?xml?version="1.0"?encoding="UTF-8"??>??<persistence?xmlns="http://java.sun.com/xml/ns/persistence"??
2. ????????????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">??
3. ????<persistence-unit?name="itcast"?transaction-type="JTA">?? ????????<jta-data-source>java:MSSQLDS</jta-data-source>??
4. ????????<properties>??????????????<property?name="hibernate.hbm2ddl.auto"?value="update"/>??
5. ????????????<property?name="hibernate.show_sql"?value="true"/>?? ????????????<property?name="hibernate.format_sql"?value="true"/>??
6. ????????</properties>??????</persistence-unit>??
7. </persistence>??

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4 dao

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1. @Stateless??@Remote(PersonService.class)??
2. public?class?PersonServiceBean?implements?PersonService{?? ????@PersistenceContext(unitName="itcast")?EntityManager?em;??
3. ??????????public?void?delete(Integer?personId)?{??
4. ????????em.remove(em.getReference(Person.class,?personId));?? ????????//返回而?代理对象 ??
5. ????}????
6. ????public?Person?getPerson(Integer?personId)?{?? ????????return?em.find(Person.class,?personId);??
7. ????}????
8. ????@SuppressWarnings("unchecked")?? ????public?List<Person>?getPersons()?{??
9. ????????return?(List<Person>)?em.createQuery("?select?p?from?Person?p?").getResultList();?? ????}??
10. ??????public?void?save(Person?person)?{??
11. ????????em.persist(person);??????}??
12. ??????public?void?update(Person?person)?{??
13. ????????em.merge(person);??????}??
14. }??

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在dao 中：

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

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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(){

}

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public enum CommentType{

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

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

???? public abstract String getName();

}

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@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