Hibernate ?单项多对1

package com.hibernate.n21;public class Order { ???private Integer orderId; ???private String orderName; ???private Customer customer; ???private Integer getOrderId() { ???????return orderId; ???} ???public void setOrderId(Integer orderId) { ???????this.orderId = orderId; ???} ???public String getOrderName() { ???????return orderName; ???} ???public void setOrderName(String orderName) { ???????this.orderName = orderName; ???} ???public Customer getCustomer() { ???????return customer; ???} ???public void setCustomer(Customer customer) { ???????this.customer = customer; ???} ???public Order(String orderName, Customer customer) { ???????super(); ???????this.orderName = orderName; ???????this.customer = customer; ???} ???}

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping package="com.hibernate.n21"> ???<class name="Order" table="orders" > ???????????????<id name="orderId" type="java.lang.Integer"> ???????????<column name="order_Id" /> ???????????<!-- 指定主键的生成方式, native: 使用数据库本地方式 --> ???????????<generator class="native" /> ???????</id> ???????????<property name="orderName" ???????????type="java.lang.String" column="order_Name" > ???????</property> ???????????????<!-- 映射n-1的关联关系 ?
　　　　　　　　name:1的属性名。把1当成多的一个属性。
　　　　　　　　class ?1的类名。
　　　　　　　　column ??1的主键名。
 --> ???????<many-to-one name="customer" class="Customer" column="customer_Id"></many-to-one> ???????????</class> ???</hibernate-mapping>

package com.hibernate.n21;public class Customer { ???private Integer customerId; ???private String customerName; ???????public Integer getCustomerId() { ???????return customerId; ???} ???public void setCustomerId(Integer customerId) { ???????this.customerId = customerId; ???} ???public String getCustomerName() { ???????return customerName; ???} ???public void setCustomerName(String customerName) { ???????this.customerName = customerName; ???} ???public Customer() { ???????super(); ???} ???public Customer(String customerName) { ???????super(); ???????this.customerName = customerName; ???} ???????}

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping package="com.hibernate.n21"> ???<class name="Customer" table="customer" > ???????????????<id name="customerId" type="java.lang.Integer"> ???????????<column name="customer_Id" /> ???????????<!-- 指定主键的生成方式, native: 使用数据库本地方式 --> ???????????<generator class="native" /> ???????</id> ???????????<property name="customerName" ????????????type="java.lang.String" column="customer_Name" > ???????</property> ???????????</class> ???</hibernate-mapping>

　　　　　<mapping resource="com/hibernate/n21/Customer.hbm.xml"/> ???????<mapping resource="com/hibernate/n21/Order.hbm.xml"/>

 1 先保存1的一端 ?只是三条insert语句。 2 @org.junit.Test 3 ????public void testN21Save(){ 4 ????????Customer customer=new Customer(); 5 ????????customer.setCustomerName("C1"); 6 ????????Order order1 =new Order(); 7 ????????order1.setOrderName("O1"); 8 ????????Order order2 =new Order(); 9 ????????order2.setOrderName("O2");10 ????????11 ????????//设置关联关系。就是给多的一方设置外键12 ????????order1.setCustomer(customer);13 ????????order2.setCustomer(customer);14 ????????session.save(customer);15 ????????session.save(order1);16 ????????session.save(order2);17 ????????18 ????}

 1 先保存多的一端。3条insert语句。2条update语句
 ????因为在插入多的一端时，无法确定1的一端的外键值。所以只能先为null。等1的一端插入后。再进行修改。 2 @org.junit.Test 3 ????public void testN21Save(){ 4 ????????Customer customer=new Customer(); 5 ????????customer.setCustomerName("C1"); 6 ????????Order order1 =new Order(); 7 ????????order1.setOrderName("O1"); 8 ????????Order order2 =new Order(); 9 ????????order2.setOrderName("O2");10 ????????11 ????????//设置关联关系。就是给多的一方设置外键12 ????????order1.setCustomer(customer);13 ????????order2.setCustomer(customer);14 ????????15 ????????session.save(order1);16 ????????session.save(order2);17 ????????session.save(customer);18 ????}