Hibernate -- 项目结构模型改造， 加 Utils 和 Dao层
示例代码：
App.java 模拟客户端
/**
* 模拟客户端
*/
public class App {
@Test
public void saveCustomer(){
CustomerDao customerDao=new CustomerDao();
Customer customer=new Customer();
customer.setName("西毒");
customerDao.saveCustomer(customer);
}
@Test
public void updateCustomer(){
CustomerDao customerDao=new CustomerDao();
Customer customer=new Customer();
customer.setId(1);
customer.setName("西门公子");
customerDao.updateCustomer(customer);
}
@Test
public void findCustomerById(){
CustomerDao customerDao=new CustomerDao();
Customer c=customerDao.getCustomerById(1);
if(c!=null){
System.out.println(c.getId()+" "+c.getName());
}
}
@Test
public void findCustomers(){
CustomerDao customerDao=new CustomerDao();
List<Customer> list=customerDao.findCustomers();
if(list!=null&&list.size()>0){
for(Customer c:list){
System.out.println(c.getId()+" "+c.getName());
}
}
}
@Test
public void deleteCustomerById(){
CustomerDao customerDao=new CustomerDao();
customerDao.deleteCustomerById(1);
}
}
CustomerDao.java Dao层代码
/**
* Dao
*/
public class CustomerDao {
public void saveCustomer(Customer customer) {
Session session=null;
Transaction tx=null;
try {
session=HibernateUtil.getSession();
if(session!=null){
tx=HibernateUtil.beginTransaction(session);
session.save(customer);
HibernateUtil.commitTransaction(tx);
}
} catch (HibernateException e) {
e.printStackTrace();
//事务回滚
HibernateUtil.rollbackTransaction(tx);
}finally{
HibernateUtil.closeSession(session);
}
}
public void updateCustomer(Customer customer) {
Session session=null;
Transaction tx=null;
try {
session=HibernateUtil.getSession();
if(session!=null){
tx=HibernateUtil.beginTransaction(session);
session.update(customer);
HibernateUtil.commitTransaction(tx);
}
} catch (HibernateException e) {
e.printStackTrace();
//事务回滚
HibernateUtil.rollbackTransaction(tx);
}finally{
HibernateUtil.closeSession(session);
}
}
public Customer getCustomerById(Serializable i) {
Session session=null;
Transaction tx=null;
Customer customer=null;
try {
session=HibernateUtil.getSession();
if(session!=null){
tx=HibernateUtil.beginTransaction(session);
customer=(Customer)session.get(Customer.class, i);
HibernateUtil.commitTransaction(tx);
}
} catch (HibernateException e) {
e.printStackTrace();
//事务回滚
HibernateUtil.rollbackTransaction(tx);
}finally{
HibernateUtil.closeSession(session);
}
return customer;
}
public List<Customer> findCustomers() {
Session session=null;
Transaction tx=null;
List<Customer> list=null;
try {
session=HibernateUtil.getSession();
if(session!=null){
tx=HibernateUtil.beginTransaction(session);
Query query=session.createQuery("from Customer c");
list=query.list();
HibernateUtil.commitTransaction(tx);
}
} catch (HibernateException e) {
e.printStackTrace();
//事务回滚
HibernateUtil.rollbackTransaction(tx);
}finally{
HibernateUtil.closeSession(session);
}
return list;
}
public void deleteCustomerById(Serializable id) {
Session session=null;
Transaction tx=null;
try {
session=HibernateUtil.getSession();
if(session!=null){
tx=HibernateUtil.beginTransaction(session);
Customer c=(Customer)session.get(Customer.class, id);
session.delete(c);
HibernateUtil.commitTransaction(tx);
}
} catch (HibernateException e) {
e.printStackTrace();
//事务回滚
HibernateUtil.rollbackTransaction(tx);
}finally{
HibernateUtil.closeSession(session);
}
}
}
HibernateUtil.java 工具类
public class HibernateUtil {
private static SessionFactory sf=null;
static{
Configuration config=new Configuration();
config.configure("cn/itcast/add/hibernate.cfg.xml");
sf=config.buildSessionFactory();
}
//获取session
public static Session getSession(){
if(sf!=null){
return sf.openSession();
}
return null;
}
//关闭session
public static void closeSession(Session session){
if(session!=null&&session.isOpen()){
session.close();
}
}
//开始事务
public static Transaction beginTransaction(Session session){
if(session!=null&&session.isOpen()){
return session.beginTransaction();
}
return null;
}
//提交事务
public static void commitTransaction(Transaction tx){
if(tx!=null&&!tx.wasCommitted()){
tx.commit();
}
}
//回滚事务
public static void rollbackTransaction(Transaction tx){
if(tx!=null&&!tx.wasRolledBack()){
tx.rollback();
}
}
}
Customer.java bean对象
/**
* 一的一端
*/
@SuppressWarnings("serial")
public class Customer implements java.io.Serializable {
private Integer id;
private String name;
//一个客户对应多个订单
private Set<Order> orderes=new HashSet<Order>(0);
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Set<Order> getOrderes() {
return orderes;
}
public void setOrderes(Set<Order> orderes) {
this.orderes = orderes;
}
}
Order.java bean对象
/**
* 多的一端
*/
public class Order {
private Integer id;
private String orderNumber;
private Double price;
//建立订单到客户的多一关联
private Customer customer;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getOrderNumber() {
return orderNumber;
}
public void setOrderNumber(String orderNumber) {
this.orderNumber = orderNumber;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
public Customer getCustomer() {
return customer;
}
public void setCustomer(Customer customer) {
this.customer = customer;
}
}
Customer.hbm.xml 配置文件
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="cn.itcast.add.Customer" table="customers">
<id name="id" type="integer">
<column name="id"/>
<generator class="increment"/>
</id>
<property name="name" type="string">
<column name="name"/>
</property>
<set name="orderes" table="orders" inverse="true">
<key>
<column name="customer_id"/>
</key>
<one-to-many class="cn.itcast.add.Order"/>
</set>
</class>
</hibernate-mapping>
Order.hbm.xml配置文件
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="cn.itcast.add.Order" table="orders">
<id name="id" type="integer">
<column name="id"/>
<generator class="increment"/>
</id>
<property name="orderNumber" type="string">
<column name="orderNumber"/>
</property>
<property name="price" type="double">
<column name="price"/>
</property>
<many-to-one name="customer" class="cn.itcast.add.Customer">
<column name="customer_id"/>
</many-to-one>
</class>
</hibernate-mapping>
hibernate.cfg.xml 配置文件
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/test</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.format_sql">true</property>
<!-- 加载映射文件-->
<mapping resource="cn/itcast/add/Customer.hbm.xml"/>
<mapping resource="cn/itcast/add/Order.hbm.xml"/>
</session-factory>
</hibernate-configuration>
关于配置文件中使用 entity-name 指向实体， 可做如下修改
Customer.hbm.xml 使用entity-name 指向实体
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<!--
entity-name:指向的名称才是在程序中真正要用到的实体的名称,可以理解成name的别名,
当entity-name存在时,entity-name优先
如果entity-name没有配置,责默认的实体的名称是name执行的类名
-->
<class name="cn.itcast.entityname.Customer" entity-name="CustomerE" table="customers">
<id name="id" type="integer">
<column name="id"/>
<generator class="increment"/>
</id>
<property name="name" type="string">
<column name="name"/>
</property>
<set name="orderes" table="orders" inverse="true">
<key>
<column name="customer_id"/>
</key>
<one-to-many entity-name="OrderE"/>
</set>
</class>
</hibernate-mapping>
这时Dao的代码则需要做相应的改变， 比如saveCustomer时 需要改为 session.save("CustomerE",customer);
必须使用指定的实体名。
