Hibernate级联关系OneToMany之 Annotation实现

 package com.lwp.hibernate.Model;

 import java.io.Serializable;

 import javax.persistence.CascadeType;
 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.FetchType;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.JoinColumn;
 import javax.persistence.ManyToOne;
 import javax.persistence.Table;

 @Entity
 @Table(name="ORDERS")
 public class Order implements Serializable{

     private static final long serialVersionUID = 1L;
     public Order(){}

     public Order(String orderNumber){
         this.orderNumber =orderNumber;
     }
     @Id
     @GeneratedValue
     @Column(name="ID")
     private Long id;

     @Column(name="ORDER_NUMBER",length=15)
     private String orderNumber;

     @ManyToOne(fetch = FetchType.EAGER,cascade=CascadeType.ALL)
     @JoinColumn(name="CUSTOMER_ID")
     private Customer customer;

     public Long getId() {
         return id;
     }

     public void setId(Long id) {
         this.id = id;
     }

     public String getOrderNumber() {
         return orderNumber;
     }

     public void setOrderNumber(String orderNumber) {
         this.orderNumber = orderNumber;
     }

     public Customer getCustomer() {
         return customer;
     }

     public void setCustomer(Customer customer) {
         this.customer = customer;
     }


 }

 package com.lwp.hibernate.Model;

 import java.io.Serializable;
 import java.util.HashSet;
 import java.util.Set;

 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.OneToMany;
 import javax.persistence.Table;

 @Entity
 @Table
 public class Customer implements Serializable{

     private static final long serialVersionUID = 1L;

     public Customer(){}
     public Customer(String name,Set<Order> orders){
         this.name=name;
         this.orders = orders;
     }

     @Id
     @GeneratedValue
     @Column(name="ID")
     private Long id;

     @Column(name="NAME",length=15)
     private String name;

     @OneToMany(mappedBy="customer")
     private Set<Order> orders = new HashSet<Order>();

     public Set<Order> getOrders() {
         return orders;
     }
     public void setOrders(Set<Order> orders) {
         this.orders = orders;
     }
     public Long getId() {
         return id;
     }

     public void setId(Long id) {
         this.id = id;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }
 }

 import java.util.HashSet;
 import java.util.Set;

 import org.hibernate.Session;
 import org.hibernate.SessionFactory;
 import org.hibernate.cfg.AnnotationConfiguration;
 import org.hibernate.cfg.Configuration;
 import org.hibernate.tool.hbm2ddl.SchemaExport;

 import com.lwp.hibernate.Model.Customer;
 import com.lwp.hibernate.Model.Order;

 public class CustomerTest {

     public static void main(String[] args) {
         new SchemaExport(new AnnotationConfiguration().configure("/hibernate.cfg.xml")).create(true, false);

         Set<Order> orders =  new HashSet<Order>();
         Order order1 = new Order("Tom_Order001");
         Order order2 = new Order("Tom_Order002");
         orders.add(order1);
         orders.add(order2);
         Customer customer = new Customer("Tom",orders);
         order1.setCustomer(customer);
         order2.setCustomer(customer);

         //save(customer);
         save(order1);
         save(order2);


     }

     public static void save(Object o){
         //Configuration cfg = new Configuration();//xx.hbm.xml形式下的new
         Configuration cfg = new AnnotationConfiguration(); //Annotation形式下的new
         SessionFactory sf = cfg.configure().buildSessionFactory();
         Session session = sf.openSession();
         session.beginTransaction();
         session.save(o);
         session.getTransaction().commit();
         session.close();
         sf.close();
     }
 }

注：这里不用save customer, save order时就会保存customer。因为mappedBy 相当于Inverse=value,既让Many一方来维护。