Hibernate双向一对多关系问题，使用Hibenrnate的人都来参与讨论一下吧！！

Question

User类：
package com.bryantd.hibernate.entity;import java.io.Serializable;
import java.util.*;import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;public class User implements Serializable {
private Integer id;
private String name;
private int age;

private Set addresses;

public User(String name, int age) {
super();
// TODO Auto-generated constructor stub
this.name = name;
this.age = age;
}

public User(){}

public Set getAddresses() {
if (addresses == null) {
return new HashSet();
}
return addresses;
}
public void setAddresses(Set addresses) {
this.addresses = addresses;
} public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
} 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;
}
}User的映射文件 user.hbm.xml:
<?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>

<class 
name="com.bryantd.hibernate.entity.User"
table="undirectional_one_to_many_user">

        <id name="id" type="java.lang.Integer">
            <column name="id" sql-type="INTEGER" not-null="true"/>
            <generator class="native"/>
        </id>

        <property name="name" type="java.lang.String">
             <column name="name" sql-type="VARCHAR"/>
        </property>

<property name="age" type="int">
<column name="age" sql-type="INTEGER"/>
</property>

<!-- We usually set the class with the associated column as the domain class. -->
<set name="addresses" table="undirectional_one_to_many_address" cascade="all" inverse="true">
<key column="user_id"/>
<one-to-many class="com.bryantd.hibernate.entity.Address"/>
</set>
    </class></hibernate-mapping>Address类：
package com.bryantd.hibernate.entity;import java.io.Serializable;
import java.util.*;import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;public class Address implements Serializable {
private Integer id;
private String address;
private String telephone;

private User user;

public Address(String address, String telephone) {
super();
// TODO Auto-generated constructor stub
this.address = address;
this.telephone = telephone;
}

public Address() {}

public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}

public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}

public String getTelephone() {
return telephone;
}
public void setTelephone(String telephone) {
this.telephone = telephone;
}

public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}

public boolean equals(Object object) {
if (!(object instanceof Address)) {
return false;
}
Address anotherAddress = (Address)object;
return new EqualsBuilder().appendSuper(super.equals(object))
                          .append(this.getAddress(), anotherAddress.getAddress())
                          .append(this.getTelephone(), anotherAddress.getTelephone())
                          .isEquals();
}

public int hashCode() {
return new HashCodeBuilder().appendSuper(super.hashCode())
                            .append(this.getAddress())
                            .append(this.getTelephone())
                            .hashCode();
} /*
public boolean equals(Object object) {
// TODO Auto-generated method stub
if (onject == this) {
    return true;
}
if (object instanceof Address) {
Address address = (Address)object;
if (getAddress() == address.getAddress()) return true;
}
return false;
} public int hashCode() {
// TODO Auto-generated method stub
return getTelephone().hashCode() * getAddress().hashCode();
}
*/
}Address的映射文件:
<?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>

<class 
name="com.bryantd.hibernate.entity.Address"
table="undirectional_one_to_many_address">

        <id name="id" type="java.lang.Integer">
            <column name="id" sql-type="INTEGER" not-null="true"/>
            <generator class="native"/>
        </id>

        <property name="address" type="java.lang.String">
             <column name="address" sql-type="VARCHAR)"/>
        </property>

<property name="telephone" type="java.lang.String">
<column name="telephone" sql-type="VARCHAR"/>
</property>

<many-to-one name="user" class="com.bryantd.hibernate.entity.User" cascade="none"
column="user_id"
not-null="true"/>
    </class></hibernate-mapping>

Answer 1

测试文件：
package com.bryantd.hibernate.test;import com.bryantd.hibernate.entity.User;
import com.bryantd.hibernate.entity.Address;import org.hibernate.cfg.Configuration;
import org.hibernate.SessionFactory;
import org.hibernate.Session;
import org.hibernate.Query;
import org.hibernate.Transaction;import java.util.*;public class UndirectionalOneToManyTest {
public static void saveObject(Session session, Object savedObject) {
Transaction transaction = session.beginTransaction();

        session.save(savedObject);

transaction.commit();
}

public static void updateObject(Session session, Object updatedObject) {
Transaction transaction = session.beginTransaction();

session.saveOrUpdate(updatedObject);

transaction.commit();
}

public static void deleteObjects(Session session, String deletedObjectName) {
Transaction transaction = session.beginTransaction();

String hql = "delete " + deletedObjectName;
Query query = session.createQuery(hql);
query.executeUpdate();

transaction.commit();
}

public static void showUsers(Session session) {
Transaction transaction = session.beginTransaction();

System.out.println("Show Users:");
String hql = "from User";
Query query = session.createQuery(hql);
List list = query.list();
Iterator userIterator = list.listIterator();
while (userIterator.hasNext()) {
User user = (User)userIterator.next();
System.out.println(user.getName());

Set addresses = user.getAddresses();
Iterator addressIterator = addresses.iterator();
while (addressIterator.hasNext()) {
Address address = (Address)addressIterator.next();
System.out.println(address.getAddress());
}
}
System.out.println();

transaction.commit();
}

public static void showAddresses(Session session) {
Transaction transaction = session.beginTransaction();

System.out.println("Show Addresses:");
String hql = "from Address";
Query query = session.createQuery(hql);
List list = query.list();
Iterator addressIterator = list.iterator();
while (addressIterator.hasNext()) {
Address address = (Address)addressIterator.next();
System.out.println(address.getAddress());

User user = address.getUser();
if (user != null) {
System.out.println(user.getName());
}
}
System.out.println();

transaction.commit();
}

public static void main(String[] args) {
Configuration configuration = new Configuration().configure();
SessionFactory sessionFactory = configuration.buildSessionFactory();
Session session = sessionFactory.openSession();

User user = new User("Bryantd", 23);
Address address1 = new Address("address1", "111111");
Address address2 = new Address("address2", "222222");

address1.setUser(user);
address2.setUser(user);

deleteObjects(session, "User");
deleteObjects(session, "Address");

saveObject(session, user);
saveObject(session, address1);
saveObject(session, address2);

user.getAddresses().add(address1);
user.getAddresses().add(address2);

updateObject(session, user);

showUsers(session);
showAddresses(session);
}
}

Answer 2

<many-to-one name="user" class="com.bryantd.hibernate.entity.User" cascade="none"
column="user_id"
not-null="true"/>在这个标签中加上 lazy="false"这个属性试一下

Answer 3

楼上的朋友，延迟加载就算是true，也不应该出现我这样的问题。因为延迟加载属性的时候user.getAddresses()时，也会将数据库中的数据读取出来，而不可能不读取。所以您提供的思路可能没什么意义。

Answer 4

address是主控方
但是address的cascade='none'
当然出现你碰到的现象

Answer 5

但是我的user方的cascade="all"阿。
主控方和级联操作是没有关系的阿。
user被保存的时候，为什么address方没有被保存？

Answer 6

级联与主控室两个不同的、互不相干的概念。夏昕的《深入浅出Hibernate》一书中对这两个概念作出了特别的说明，这是两个不同的概念。