当前页面: 开发资料首页 → J2EE 专题 → 在JSE环境中使用Hibernate EntityManger
摘要: 大家都知道在EJB3中 使用EntityManger来操作持久化数据,Hibernate也实现了与EJB3完全兼容并且功能更强的EntityManger,配合Hibernate Annotation一起使用 可以说在数据持久化方面与EJB3几乎没有区别了,技术最终汇聚到了一起.可见现在技术发展的趋势. 本文讲解了如何在JSE中使用EntityManager
/*
* Created on 2006-2-5
* @author icerain
*/
package test.test;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.EntityResult;
import javax.persistence.FieldResult;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.SqlResultSetMapping;
@Entity(name = "Item")
// @SqlResultSetMapping(name = "getItem", entities =
// @EntityResult(name = "org.hibernate.ejb.test.Item", fields = {
// @FieldResult(name = "name", column = "itemname"),
// @FieldResult(name = "descr", column = "itemdescription")
// })
//)
//@Cache(region="Item", usage=NONSTRICT_READ_WRITE)
public class Item implements Serializable {
private String name;
private String descr;
//private Setdistributors;
public Item() {
}
public Item(String name, String desc) {
this.name = name;
this.descr = desc;
}
@Column(length = 200)
public String getDescr() {
return descr;
}
public void setDescr(String desc) {
this.descr = desc;
}
@Id
@Column(length = 30)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
// @OneToMany
// public SetgetDistributors() {
// return distributors;
// }
//
// public void setDistributors(Setdistributors) {
// this.distributors = distributors;
// }
//
// public void addDistributor(Distributor d) {
// if ( distributors == null ) distributors = new HashSet();
// distributors.add( d );
// }
}
/*
* Created on 2006-2-5
* @author icerain
*/
package test.test;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Map;
import java.util.Properties;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import org.hibernate.cfg.Environment;
import org.hibernate.ejb.Ejb3Configuration;
import org.hibernate.ejb.HibernatePersistence;
public class TestConfig {
private EntityManagerFactory emf = null;
public TestConfig() {
this(null);
}
public TestConfig(String fileName) {
// 利用Ejb3Configuration来建立EntityManagerFactory
emf = new Ejb3Configuration().addAnnotatedClass(Item.class).createEntityManagerFactory(); //(1) 看下面解释
//emf = Persistence.createEntityManagerFactory("manager1"); // 在JSE环境中不可以使用??? (2) 看下面解释
System.out.println("Create EMF:::::");
// 利用HibernatePersistence来建立EntityManagerFactory
//emf = new HibernatePersistence().createEntityManagerFactory(getConfig()); //(3) 看下面解释
}
public Properties loadProperties() {
Properties props = new Properties();
InputStream stream = Persistence.class.getResourceAsStream( "/hibernate.properties" );
if ( stream != null ) {
try {
props.load( stream );
}
catch (Exception e) {
throw new RuntimeException( "could not load hibernate.properties" );
}
finally {
try {
stream.close();
}
catch (IOException ioe) {
}
}
}
props.setProperty( Environment.HBM2DDL_AUTO, "create-drop" );
return props;
}
private Map getConfig() {
Map config = loadProperties();
ArrayListclasses = new ArrayList ();
classes.add(Item.class);
config.put( HibernatePersistence.LOADED_CLASSES, classes );
return config;
}
public void testEntityManager() { // 测试持久化数据操作 (4)
Item item = new Item( "Mouse1", "Micro$oft mouse" );
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
em.persist( item );
System.out.println( em.contains( item ) );
em.getTransaction().commit();
System.out.println(em.contains(item));
em.getTransaction().begin();
item = (Item) em.createQuery( "from Item where descr like 'M%'" ).getSingleResult();
System.out.println(item.getDescr() + ":" + item.getName());
item.setDescr( "Micro$oft wireless mouse" );
em.getTransaction().commit();
System.out.println(item.getDescr() + ":" + item.getName());
em.close();
closeEMF();
}
public void closeEMF() {
emf.close();
System.out.println("EMF is closed..");
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
new TestConfig().testEntityManager();
}
}
#Created by JInto - www.guh-software.de
#Sun Feb 05 22:38:30 CST 2006
hibernate.cache.provider_class=org.hibernate.cache.HashtableCacheProvider
hibernate.cache.region_prefix=hibernate.test
hibernate.connection.driver_class=com.mysql.jdbc.Driver
hibernate.connection.password=329
hibernate.connection.pool_size=1
hibernate.connection.url=jdbc\:mysql\://localhost/test3
hibernate.connection.username=root
hibernate.default_batch_fetch_size=8
hibernate.dialect=org.hibernate.dialect.MySQLDialect
hibernate.hbm2ddl.auto=update
hibernate.jdbc.batch_versioned_data=true
hibernate.jdbc.use_streams_for_binary=true
hibernate.max_fetch_depth=1
hibernate.order_updates=true
hibernate.proxool.pool_alias=pool1
hibernate.query.substitutions=true 1, false 0, yes 'Y', no 'N'
javax.persistence.provider=org.hibernate.ejb.HibernatePersistence