前段時間一直在研究hibernate的one-to-many,看了不少資料也在本論壇上求教過,但由於本人對Hibernate研究的時間不是很長,所以花了不少時間和精力.昨天終於弄出來了,現在與大家分享,希望對初學者有幫助!

1、設定資料庫，本人使用的資料庫是Oracle 9i
   設定hibernate.properties
   ## Oracle

   hibernate.dialect net.sf.hibernate.dialect.Oracle9Dialect
   #hibernate.dialect net.sf.hibernate.dialect.OracleDialect
   hibernate.connection.driver_class oracle.jdbc.driver.OracleDriver
   hibernate.connection.username sa
   hibernate.connection.password sa
   hibernate.connection.url jdbc:oracle:thin:@xxx.xxx.xxx.xxx:1521:myoracle

2、假設一個使用者可以同時有幾個帳戶，能通過帳戶對應到使用者，即為一個雙向的one-to-many.這是引用我在論壇上發表的文章的回覆，很謝謝geniouc給我的參考。

3、javaBean: customer & account
  

1.   public
    class Customer {
2.   private  cid;
3.   private  custName;
4.   private Set accounts= new HashSet();
5.   public Customer(){
6.   }
7.   public  getCid() {
8.     return cid;
9.   }
10.   public void setCid( cid) {
11.     this.cid = cid;
12.   }
13.   public  getCustName() {
14.     return custName;
15.   }
16.   public void setCustName( custName) {
17.     this.custName = custName;
18.   }
19.   public Set getAccounts(){
20.      return accounts;
21.   }
22.   public void setAccounts(Set accounts){
23.      this.accounts = accounts;
24.   }
25. }
26.   public class Account {
27.   private long aid;
28.   private  accNumber;
29.   private Customer customer;
30.   public Account(){
31.   }
32.   public long getAid() {
33.     return aid;
34.   }
35.   public void setAid(long aid) {
36.     this.aid = aid;
37.   }
38.   public  getAccNumber() {
39.     return accNumber;
40.   }
41.   public void setAccNumber( accNumber) {
42.     this.accNumber = accNumber;
43.   }
44.   public Customer getCustomer(){
45.      return customer;
46.   }
47.   public void setCustomer(Customer customer){
48.      this.customer = customer;
49.   }
50. }

4、xml配置檔案中：(關係的建立)
Account.hbm.xml

1. <?xml version="1.0"?>
2. <!DOCTYPE hibernate-mapping
3.     PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
4.     "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
5. <hibernate-mapping> 
6.     <class name="one2many.Account" table="Account"> 
7.         <id name="aid" type="long" column="aid" unsaved-value="0"> 
8.             <generator class="increment"/> 
9.         </id>
10.         <property name="accNumber" type="string"/>
11.         <many-to-one name="customer" column="cidForCustomer"/> 
12.     </class>
13. </hibernate-mapping>

Customer.hbm.xml

1. <?xml version="1.0"?>
2. <!DOCTYPE hibernate-mapping
3.     PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
4.     "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
5. <hibernate-mapping>
6.     <class name="one2many.Customer" table="Customer">
7.     <id name="cid" type="string" column="cid"> 
8.             <generator class="assigned"/> 
9.         </id>
10.     <property name="custName" type="string"/>        
11.      <set name="accounts" lazy="true" inverse="true" cascade="all" >
12.      <key column="cidForCustomer"/>
13.      <one-to-many class="one2many/Account"/>
14.      </set>
15.     </class> 
16. </hibernate-mapping>

5、測試程式，Test.java

1. package one2many;
2. import net.sf.hibernate.*;
3. import net.sf.hibernate.cfg.*;
4. public class Test {
5. public static void main([] args) throws HibernateException {
6.      Configuration conf= new Configuration();
7.      conf.addClass(Account.class);
8.      conf.addClass(Customer.class);
9.      SessionFactory sessionFactory = conf.buildSessionFactory();
10.      Customer cust = new Customer();
11.      cust.setCid("aa");
12.      cust.setCustName("Kelvin");
13.      Account acc = new Account();
14.      acc.setAccNumber("acc");
15.      acc.setCustomer(cust);
16.      Account acc1 = new Account();
17.      acc1.setAccNumber("acc1");
18.      acc1.setCustomer(cust);
19.      cust.getAccounts().add(acc);
20.      cust.getAccounts().add(acc1);
21.      Session session = sessionFactory.openSession();
22.      Transaction tx= session.beginTransaction();
23.      session.save(cust);
24.      tx.commit();
25.      session.close();
26.      sessionFactory.close();
27.  }