一个完整的hibernate的one-to-many的例子

前段时间一直在研究hibernate的one-to-many,看了不少资料也在本论坛上求教过,但由于本人对Hibernate研究的时间不是很长,所以花了不少时间和精力.昨天终于弄出来了,现在与大家分享,希望对初学者有帮助!

1、设置数据库，本人使用的数据库是Oracle 9i
   设置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、假设一个用户可以同时有几个帐户，能通过帐户对应到用户，即为一个双向的one-to-many.这是引用我在论坛上发表的文章的回复，很谢谢geniouc给我的参考。

3、javaBean: customer & account
 

   1.   public class Customer {
   2.   private String cid;
   3.   private String custName;
   4.   private Set accounts= new HashSet();
   5.
   6.   public Customer(){
   7.   }
   8.   public String getCid() {
   9.     return cid;
  10.   }
  11.   public void setCid(String cid) {
  12.     this.cid = cid;
  13.   }
  14.   public String getCustName() {
  15.     return custName;
  16.   }
  17.   public void setCustName(String custName) {
  18.     this.custName = custName;
  19.   }
  20.
  21.   public Set getAccounts(){
  22.      return accounts;
  23.   }
  24.
  25.   public void setAccounts(Set accounts){
  26.      this.accounts = accounts;
  27.   }
  28.
  29. }
  30.
  31.   public class Account {
  32.   private long aid;
  33.   private String accNumber;
  34.   private Customer customer;
  35.
  36.   public Account(){
  37.   }
  38.   public long getAid() {
  39.     return aid;
  40.   }
  41.   public void setAid(long aid) {
  42.     this.aid = aid;
  43.   }
  44.   public String getAccNumber() {
  45.     return accNumber;
  46.   }
  47.   public void setAccNumber(String accNumber) {
  48.     this.accNumber = accNumber;
  49.   }
  50.
  51.   public Customer getCustomer(){
  52.      return customer;
  53.   }
  54.
  55.   public void setCustomer(Customer customer){
  56.      this.customer = customer;
  57.   }
  58. }



4、xml配置文件中：(关系的建立)
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.
  12.      <set name="accounts" lazy="true" inverse="true" cascade="all" >
  13.      <key column="cidForCustomer"/>
  14.      <one-to-many class="one2many/Account"/>
  15.      </set>
  16.
  17.     </class>
  18. </hibernate-mapping>


5、测试程序，Test.java

   1. package one2many;
   2.
   3. import net.sf.hibernate.*;
   4. import net.sf.hibernate.cfg.*;
   5.
   6. public class Test {
   7. public static void main(String[] args) throws HibernateException {
   8.
   9.      Configuration conf= new Configuration();
  10.      conf.addClass(Account.class);
  11.      conf.addClass(Customer.class);
  12.      SessionFactory sessionFactory = conf.buildSessionFactory();
  13.
  14.      Customer cust = new Customer();
  15.      cust.setCid("aa");
  16.      cust.setCustName("Kelvin");
  17.
  18.      Account acc = new Account();
  19.      acc.setAccNumber("acc");
  20.      acc.setCustomer(cust);
  21.
  22.      Account acc1 = new Account();
  23.      acc1.setAccNumber("acc1");
  24.      acc1.setCustomer(cust);
  25.
  26.      cust.getAccounts().add(acc);
  27.      cust.getAccounts().add(acc1);
  28.
  29.      Session session = sessionFactory.openSession();
  30.      Transaction tx= session.beginTransaction();
  31.      session.save(cust);
  32.
  33.      tx.commit();
  34.      session.close();
  35.
  36.      sessionFactory.close();
  37.  }
  38. }