ejb加數(shù)據(jù)庫的簡單例子

環(huán)境和那個沒有數(shù)據(jù)庫的一樣1?添加數(shù)據(jù)源文件到j(luò)boss的發(fā)布目錄中：在jboss的jboss-4.2.2.GA\docs\examples\jca目錄中找一個*-dx.xml配置數(shù)據(jù)源的文件，我用的是mysql,所以把mysql-ds.xml復(fù)制到\jboss-4.2.2.GA\server\default\deploy目錄中然后修改它:我的文件內(nèi)容如下:<?xmlversion=ll1.0"encoding=,,UTF-8,,?><!-$ld:mysql-ds.xml631752007-05-2116:26:06Zrrajesh$-><!-DatasourceconfigforMySQLusing3.0.9availablefrom:/downloads/api-jdbc-stable.html-><datasources><local-tx-datasource><jndi?name>MySqlDS</jndi?name><connection-url>jdbc:mysql://localhost:330^test</connection-url><driver-class>com?mysql?jdbc?Driver</drive「class><user-name>root</user?name〉<password>root</password><exception-sorter-class?name>org?jboss?resource?adapter?jdbc?vendor?MySQLExceptionSorter</exception?sorter?class?name><!-shouldonlybeusedondriversafter3.22.1with"ping"support<valid-connection?checker?class?name'org.jboss.resource.adapter.jdbc.vendor.MySQLValidConnectionChecker</valid-connection?checker?class?name〉-><!-sqltocallwhenconnectioniscreatedew-connection?sq卜somearbitrarysql</new?connectiorvsq卜-><!一sqltocallonanexistingpooledconnectionwhenitisobtainedfrompool?MySQLValidConnectionCheckerispreferredfornewerdrivers<check-valid-connection-sql>somearbitrarysql</check-valid-connection-sql>-><!一correspond!ngtype?mappinginthestandardjbosscmp-jdbc.xml-><metadata><type-mapping>mySQL</type?mapping></metadata></local-tx-datasource></datasources>2?建一個ejb工程，注意：這個要把AddsupportforEntitybeans(addJPAcapabilities)選中,J2EESpecificationLevel:選擇javaEE5.0-EJB3Z那個沒帶數(shù)據(jù)庫的也是選擇那個。

jfKuencnyectMyEdipseRunWindow旦elpr6心NewEJBProjectCreateanEJBProjectCreateanEJBprojectintheworkspaceoranexternallocation|u『E)~jsks3vinated>5tomEJBProjectDetailsProjectNameTestEjb3WithDataBaseLocationLZUsedefaultlocationDirectoryD:\workSpace\TestEjb3WithDataBaseSourcefoldersrcJ2EESpecificationLeveloJavaEE5.0?EJB3J2EE1.4?jfKuencnyectMyEdipseRunWindow旦elpr6心NewEJBProjectCreateanEJBProjectCreateanEJBprojectintheworkspaceoranexternallocation|u『E)~jsks3vinated>5tomEJBProjectDetailsProjectNameTestEjb3WithDataBaseLocationLZUsedefaultlocationDirectoryD:\workSpace\TestEjb3WithDataBaseSourcefoldersrcJ2EESpecificationLeveloJavaEE5.0?EJB3J2EE1.4?EJB2CJ2EE1.3?EJB1Browse-PersistenceConfigurationJAddsupportforEntitybeans(addJPAcapabilities)iIfpersistencesupportisnotaddednow,nopersistence.xmlfilewillbecreatedandentitybeansupportwillbeunavailable?Toaddpersistencesupportatalatertime,pleaseaddJPACapabilitiestothisproject”NewEJBProjectCreateanEJBProjectGDataSourceJNDIpathisundefinedJPAPersistencePersistenceUnitName:TestEjb3WithDataBasePUJNDIDataSource:<UseJavaTransactionAPIsDesign-timePersisteneeToolsConfigurationZSpecifyJPADatasourcedetailsDriver:CreatenewDriverCatalog/Schema:UpdateListiSelect!ngtheUpdateListbuttonrequiresthedrivertorefreshitsmetadata.ThiswillcausetheDBBrowsertoresetasitsynchronizeswithupdatedschema/cataloginformation.;sesti;sest注意：上面的JNDIDataSource:寫上：java:/MySqlDS,紅色部分是和上面的*-ds.xml的數(shù)據(jù)源

配置文件中<jndi-name>MySqlDS</jndi-name>jndi-name一樣的。接著要配置Driver,點擊后面的連接:CreatenewDriver,出現(xiàn)如下對話框：NewDatabaseConnectionDriverCreateanewconnectiondriverDrivertemplate:Drivername:ConnectionURL:Username:Password:DriverJARsDriverclassname:TestDriverjdbc:axiondb:<database?NewDatabaseConnectionDriverCreateanewconnectiondriverDrivertemplate:Drivername:ConnectionURL:Username:Password:DriverJARsDriverclassname:TestDriverjdbc:axiondb:<database?name>[:<database-directory>]ConnecttodatabaseonMyEclipsestartupSavepasswordAddJARsRemoveDrivertemplate:選擇你對于數(shù)據(jù)庫的，Drivername:隨便取個名字，中間幾項應(yīng)當不用說了，最后在DriverJARS:點擊AddJARs,添加對應(yīng)數(shù)據(jù)庫的驅(qū)動。我的配置如卞：

yirEditDatabaseConnectionDriverEdittheconnectiondriveryirEditDatabaseConnectionDriverEdittheconnectiondriverDrivertemplate:Drivername: mysqlConnectionURL:jdbc:mysql://localhost:3306/testUsername: rootPassword: ""DriverJARsE:\soft\編程軟件\mysqljar |AddJARsRemoveDriverclassname:com.mysql.jdbc.DriverTestDriver匚ConnecttodatabaseonMyEdipsestartupVISavepassword點擊finish后，回到上一個界面，點擊updatelist,然后選擇一個數(shù)據(jù)庫：我的如下:

createantJbHrojectConfigureJPApersistenceJPAPersistencePersistenceUnitName:TestEjb3WithDataBasePUJNDIDataSource: java:/MySqlDSJUseJavaTransactionAPIsDesign-timePersistenceToolsConfigurationI'ZSpecifyJPADatasourcedetailsDriver:CreatenewDriverUpdateListCatalog/Schema:iSelectingtheUpdateListbuttonrequiresthedrivertorefreshitsmetadata.ThiswillcausetheDBBrowsertoresetasitsynchronizeswithupdatedschema/cataloginformation.CreatenewDriverUpdateListCatalog/Schema:iMyEdipseJavaPersisteneeToolsusedesign-timesettingstoprovidedatabasemetadatavalidationandcontent-assist.YourJNDIdatasourceandapplicationserverconfigurationwillnotbeaffected.Tochangethesesettingsatalatertimesee:Project>Properties>MyEclipse>Persistenee點擊finish?接著配置類庫：和昨晚那個一樣步驟配置：注意多加了一個數(shù)據(jù)庫的驅(qū)動jar,我的如下:I II 八 12.在srcF建三個包org.test.modelorg.test.dao^rg.test.service.首先在org.test.model中建兩個類Customer,Orders.?代碼如下，注意其中的注解和數(shù)據(jù)庫的映射(和hibernate—*樣)。哦，還要注意那個兩個實體都要實現(xiàn)Serializable接口。Customex1?javapackageorg.test.model;importjava.io.Serializable;importjava.util.HashSet;importjava.util.Set;importjavax.persistence.CascadeType;importjavax.persistence.Column;importjavax.persistence.Entity;importjavax.persistence.FetchType;importjavax.persistence.GeneratedValue;importjavax.persistence.GenerationType;importjavax.persistence」d;importjavax.persistence.OneToMany;@Entity(name="customer")publicclassCustomerimplementsSerializable{*/privatestaticfinallongserialVersionlllD=7139471850142077544L;privateLongid;privateStringname;privateSet<Orders>orders=newHashSet<Orders>();@ld@GeneratedValue(strategy=GenerationType.AUTO)publicLonggetld(){returnid;}publicvoidsetld(Longid){this.id=id;}@Column(name="name",length=20,ntillable=true)publicStringgetName(){returnname;}publicvoidsetName(Stringname){this,name=name;}@OneToMany(mappedBy="customer"”cascade={CascadeType.ALL},fetchFetchType.LAZY)publicSet<Orders>getOrders(){returnorders;}publicvoidsetOrders(Set<Orders>orders){this.orders=orders;}}Orders.javapackageorg.test.model;importjava.io.Serializable;importjavax.persistence.Column;importjavax.persistence.Entity;importjavax.persistence.FetchType;importjavax.persistence.GeneratedValue;importjavax.persistence.GenerationType;importjavax.persistence.Id;importjavax.persistenceJoinColumn;importjavax.persistence.ManyToOne;@Entity(name="orders1')publicclassOrdersimplementsSerializable{*/privatestaticfinallongserialVersionlllD=9110483244450845026L;privateLongid;privateStringname;privateCustomercustomer;@ld@GeneratedValue(strategy=GenerationType.AUTO)publicLonggetld(){returnid;}publicvoidsetld(Longid){this.id=id;}@Column(name="name",length=20,ntillable=true)publicStringgetName(){returnname;}publicvoidsetName(Stringname){this,name=name;}@ManyToOne(fetch=FetchType丄AZY)@JoinColumn(name=,lcutomerjd",nullable=true,unique=false,insertable=true,updatable=true)publicCustomergetCustomer(){returncustomer;}publicvoidsetCustomer(Customercustomer){this.customer=customer;3?在org.test.dao中建個接I丨CoreDAO.其中都是一些數(shù)據(jù)庫的操作(CRUD)?注意這里用了泛型定義實體和實體記。CoreDAO.javapackageorg.test.dao;importjava.io.Serializable;importjava.util.List;publicinterfaceCoreDAOcTJDextendsSerializable>{publicTfindByld(IDid);publicList<T>findAll();publicvoiddelete(Tentity);publicintdeleteAll();publicvoidsave(Tentity);publicTupdate(Tentity);publicList<T>findByProperty(StringpropertyName,finalObjectvalue,finalint..?rowStartldxAndCount);}4?建個包org.test.dao.impl.在其中建個抽象類CoreDAOImpL代碼如下:CoreDAOImpl.javapackageorg.test.dao.impl;importjava.io.Serializable;importjava.util.List;importjavax.persistence.EntityManager;importjavax.persistence.Query;importorg.test.dao.CoreDAO;publicabstractclassCoreDAOImpl<T,IDextendsSerializable>implementsCoreDAO<T,ID>{privateClass<T>entityBeanType;privateEntityManagerem;publicCoreDAOImpl(Class<T>type,EntityManagerem){this.entityBeanType=type;this.em=em;}publicCoreDAOImpl(Class<T>type){this.entityBeanType=type;}publicvoidsetEntityManager(EntityManagerem){this.em=em;}protectedEntityManagergetEntityManager(){if(em==null)thrownewHlegalStateException("EntityManager初始化異常！”);returnem;}publicClass<T>getEntityBeanType(){returnentityBeanType;}publicTfindByld(IDid){returngetEntityManager().find(getEntityBeanTypef),id);}@SuppressWarnings(Hunchecked")publicList<T>findAll(){Stringquery=''fromu+getEntityBeanType()?getName();returngetEntityManager().createQuery(query).getResultList();}publicvoiddelete(Tentity){try{getEntityManager()?remove(entity);}catch(RuntimeExceptionre){throwre;publicintdeleteAII(){intnumberDeleted=0;try{Stringname=getEntityBeanType()?getName();Queryq=em.createQuery("DELETEFROM"+name);numberDeleted=q.executeUpdate();}catch(RuntimeExceptionre){throwre;}returnnumberDeleted;}publicvoidsave(Tentity){try{getEntityManager().persist(entity);}catch(RuntimeExceptionre){throwre;}}publicTupdate(Tentity){try{Tresult=getEntityManager().merge(entity);returnresult;}catch(RuntimeExceptionre){throwre;}}@SuppressWarnings(Hunchecked")publicList<T>findByProperty(StringpropertyName,finalObjectvalue,finalint…rowStartldxAndCount){try{Stringname=getEntityBeanType()?getName();finalStringqueryString=String.format("from%swhere%s=:propertyValue1',name,propertyName);Queryquery=getEntityManager().createQuery(queryString);query.setParameter(,,propertyValue,,/value);if(rowStartIdxAndCount!=null&&rowStartldxAndCount.length>0){introwStartldx=Math.max(0zrowStartldxAndCount[0]);if(rowStartldx>0){query.setFirstResult(rowStartldx);if(rowStartldxAndCount.length>1){introwCount=Math.max(0,rowStartldxAndCount[l]);if(rowCount>0){query.setMaxResults(rowCount);}}}returnquery.getResultList();}catch(RuntimeExceptionre){throwre;}}}5?在org.test.dao中建一個接IICustomerDAO.代碼如卜CustomerDAO.javapackageorg?test?dao;importorg.test.model.Customer;publicinterfaceCustomerDAOextendsCoreDAO<CustomerzLong>{}6?在org.test.dao.impl中建一個類CustomerDAOImpL它繼承抽象的CoreDAOImpI并實現(xiàn)CustomerDAO.代碼如下:CustomerDAOImpl.javapackageorg.test.dao.impl;importjavax.persistence.EntityManager;importorg.test.dao.CustomerDAO;importorg.test.model.Customer;publicclassCustomerDAOImpIextendsCoreDAOImpl<CustomerzLong> implementsCustomerDAO{publicCustomerDAOImpl(EntityManagerem){super(Customer.classzem);7?在org.test.service中建兩個接IIServiceBeanLocaLServiceBeanRemote,代碼如下:ServiceBeanLocal.javapackageorg.test.service;importjava.util.List;importorg.test.model.Customer;publicinterfaceServiceBeanLocal{publicList<Customer>findCustomers();}ServiceBeanRemote.javapackageorg?test?service;publicinterfaceServiceBeanRemoteextendsServiceBeanLocal{}8?建一個包org.test.service.impl在其中建一個類ServiceBean并實現(xiàn)上面兩個接I1,代碼如2注意其中的注解。ServiceBean.javapackageorg.test.service.impl;importjava.util.List;importjavax.ejb.Local;importjavax.ejb.Remote;importjavax.ejb.Stateless;importjavax.persistence.EntityManager;importjavax.persistence.PersistenceContext;importjavax.persistence.PersistenceContextType;importorg.test.dao.CustomerDAO;importorg.test.dao.impl.CustomerDAOImpI;importorg.test.model.Customer;importorg.test.service.ServiceBeanLocal;importorg.test.service.ServiceBeanRemote;@Stateless(name二"service”)@Local(ServiceBeanLocal.class)@Remote(ServiceBeanRemote.class)publicclassServiceBeanimplementsServiceBeanLocal,ServiceBeanRemote{@PersistenceContext(unitName=,'TestEjb3WithDataBasePU,,/type=PersistenceContextType.TRANSACTION)privateEntityManagerem;privateCustomerDAOcustomerDAO;publicList<Customer>findCustomers(){returngetCustomerDAO().findAII();}publicCustomerDAOgetCustomerDAO(){if(this.customerDAO==null){this.customerDAO=newCustomerDAOImpl(em);}returnthis.customerDAO;}}注意:@Stateless(name=,,serviceH)中的name,它是用來改變bean發(fā)布的時候jndi的名字的，沒加name的話默認是bean的類名。@PersistenceContext()中的unitName和自動生的persistence.xml(它在src/META-INF中)中的<persistence-unit>的name一樣。9?修改配置文件persistence.xml我的文件內(nèi)容如下：<?xmlversion=,fl?0”encoding=uUTF-8,f?><persistencexmlns=Mhttp://java?sun?com/xml/ns/pe工sistence"xmlns:xsi=,'http://www?w3?org/2001/XMLSchema一instance"xsi:schemaLocation=,,http://java?sun?com/xml/ns/persistenuehttp://java?sun.com/xml/ns/persistence/persis ?xsdHversion=Hl?0”><persistence-unitname=uTestEjb3WithDataBasePUHtransaction-typG="<provider>org?hibernate?ejb?HibernatePe工sistenceC/provider〉<jta-data-source〉java:/MySqlDS</jta-data-source><class>org?test?model?Customer</class><class>org?test?model?Orders</class><properties><propertyname=Mhibernate?dialect1'value=uorg.hibernate?