Hibernate 一对多的联系（Set关联） 对象关系映射

配置xml文件

有两个，在主配置文件中配置一对多的联系：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
          "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
          "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
          
<hibernate-mapping>
<class name="star.july.d_one2many.User" table="o_user">
                             <id name="id" column="uid">
                                      <generator class="native"></generator>
                             </id>
                             <property name="name" column="name"></property>
                             <!-- 一对多set集合映射
                                      table：不需要配置
                                      key，外键
                                      cascade:
                                                save-update:保存和更新操作
                                                delete：删除操作
                                                all：save-update+delete
                             -->
                             <set name="address" cascade="save-update">
                                      <key column="uid"></key>
                                      <one-to-many class="star.july.d_one2many.Address"/>
                             </set>
                   </class>
                   
          
</hibernate-mapping>

另一个配置文件，存放地址的：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
          "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
          "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
          
<hibernate-mapping>
<class name="star.july.d_one2many.Address" table="t_address">
                             <id name="id" column="id">
                                      <generator class="native"></generator>
                             </id>
                             <property name="name" column="name"></property>
                             <property name="zipcode" column="zipcode"></property>
                             <property name="phone" column="phone"></property>
                             <property name="address" column="address"></property>
                   </class>
                   
          
</hibernate-mapping>

创建实体类

在主类中创建关联对象：

package star.july.d_one2many;
import java.util.HashSet;
import java.util.Set;
public class User {
    private int id;
    private String name;
    //关联对象
    private Set<Address> address =new HashSet<Address>();
    
    public Set<Address> getAddress() {
        return address;
    }
    public void setAddress(Set<Address> address) {
        this.address = address;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    
    @Override
    public String toString() {
        return "User [id=" + id + ", name=" + name + ", address=" + address
                + "]";
    }
    
    
}

存放地址类

package star.july.d_one2many;
public class Address {
    private int id;
    private String name;
    private String zipcode;
    private String phone;
    private String address;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getZipcode() {
        return zipcode;
    }
    public void setZipcode(String zipcode) {
        this.zipcode = zipcode;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    @Override
    public String toString() {
        return "Address [id=" + id + ", name=" + name + ", zipcode=" + zipcode
                + ", phone=" + phone + ", address=" + address + "]";
    }
    
    
}

测试：

package star.july.d_one2many;
import java.util.Set;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;
import star.july.util.HibernateUtil;
//set集合
public class SetDemo {
    //添加
    @Test
    public void test1(){
        Session session = HibernateUtil.getSession();
        //获取事务对象
        Transaction ts = session.getTransaction();
        try{
            ts.begin();
            
            //创建对象
            User u = new User();
    //      u.setId(3);
            u.setName("小年");
            
            Address address = new Address();
            address.setName("姜妮");
            address.setPhone("1392388948");
            address.setZipcode("524088");
            address.setAddress("北凉龙虎山");
            
            Address address2 = new Address();
            address2.setName("大红薯");
            address2.setPhone("1567384048");
            address2.setZipcode("524000");
            address2.setAddress("北莽");
            
            //保存收货地址
            u.getAddress().add(address);
            u.getAddress().add(address2);
            
            session.save(u);
//          session.save(address);
            
            
            ts.commit();
            HibernateUtil.close(session);
        }catch(Exception e){
            e.printStackTrace();
            ts.rollback();
        }
        
    }
    
    
    
    //查询
    @Test
    public void test2(){
        Session session = HibernateUtil.getSession();
        //获取事务对象
        Transaction ts = session.getTransaction();
        try{
            ts.begin();
        
            User u = (User)session.get(User.class, 2);
            Set<Address> ads = u.getAddress();
            //对象遍历输出
            for(Address a : ads){
                System.out.println(a);
            }
            ts.commit();
            HibernateUtil.close(session);
        }catch(Exception e){
            e.printStackTrace();
            ts.rollback();
        }
        
    }
    
    
    
    
    //修改
        @Test
        public void test3(){
            Session session = HibernateUtil.getSession();
            //获取事务对象
            Transaction ts = session.getTransaction();
            try{
                ts.begin();
                
                //先查询会员
                User u  = (User)session.get(User.class, 2);
                //再修改
                Address a = (Address) session.get(Address.class, 3);
                //移除两者之间的关系，即把外键变为null
                u.getAddress().remove(a);
                //删除收货地址
                session.delete(a);
                
                ts.commit();
                HibernateUtil.close(session);
            }catch(Exception e){
                e.printStackTrace();
                ts.rollback();
            }
            
        }
}