hibernate学习（设计一对多 关系 映射）

1，配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
    <!-- 指定连接数据库所用的驱动 -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <!-- 指定连接数据库的url，其中hibernate是本应用连接的数据库名 -->
        <property name="connection.url">jdbc:mysql://localhost:3306/hibernate02?useUnicode=true&amp;characterEncoding=utf-8 </property>
        <!-- 指定连接数据库的用户名 -->
        <property name="connection.username">root</property>
        <!-- 指定连接数据库的密码 -->
        <property name="connection.password">123456</property>
        <!-- 指定连接池里最大连接数 -->
        <property name="hibernate.c3p0.max_size">20</property>
        <!-- 指定连接池里最小连接数 -->
        <property name="hibernate.c3p0.min_size">1</property>
        <!-- 指定连接池里连接的超时时长 -->
        <property name="hibernate.c3p0.timeout">5000</property>
        <!-- 指定连接池里最大缓存多少个Statement对象 -->
        <property name="hibernate.c3p0.max_statements">100</property>
        <property name="hibernate.c3p0.idle_test_period">3000</property>
        <property name="hibernate.c3p0.acquire_increment">2</property>
        <property name="hibernate.c3p0.validate">true</property>
        <!-- 指定数据库方言 -->
        <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
        <!-- 根据需要自动创建数据表 -->
        <property name="hbm2ddl.auto">update</property><!--①-->
        <!-- 显示Hibernate持久化操作所生成的SQL -->
        <property name="show_sql">true</property>
        <!-- 将SQL脚本进行格式化后再输出 -->
        <property name="hibernate.format_sql">true</property>
        <!-- 罗列所有持久化类的类名 -->

        <mapping class="org.crazy.app.domain.Person"/>
        <mapping class="org.crazy.app.domain.Address"/>
        </session-factory>
</hibernate-configuration>

2，写 hibernateutil

package lee;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;

public class HibernateUtil {
    public static final SessionFactory sessionFactory;
    static
    {
        try
        {
            // 使用默认的hibernate.cfg.xml配置文件创建Configuration实例
            Configuration cfg = new Configuration()
                .configure();
            // 以Configuration实例来创建SessionFactory实例
            ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
                .applySettings(cfg.getProperties()).build();
            sessionFactory = cfg.buildSessionFactory(serviceRegistry);
        }
        catch (Throwable ex)
        {
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    // ThreadLocal可以隔离多个线程的数据共享，因此不再需要对线程同步
    public static final ThreadLocal<Session> session
        = new ThreadLocal<Session>();

    public static Session currentSession()
        throws HibernateException
    {
        Session s = session.get();
        // 如果该线程还没有Session,则创建一个新的Session
        if (s == null)
        {
            s = sessionFactory.openSession();
            // 将获得的Session变量存储在ThreadLocal变量session里
            session.set(s);
        }
        return s;
    }
    public static void closeSession()
            throws HibernateException
        {
            Session s = session.get();
            if (s != null)
                s.close();
            session.set(null);
        }
}

3,java beans

//父亲
package org.crazy.app.domain;

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

import javax.persistence.*;

import org.hibernate.annotations.Cascade;
import org.hibernate.annotations.CascadeType;

@Entity
@Table(name="person_inf")
public class Person {
    @Id
    @Column(name="person_id")
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;
    public Person() {
    }
    private String name;
    private  int age;
    @OneToMany(targetEntity=Address.class,mappedBy="person")
    private Set<Address> addresses=new HashSet<Address>();
    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;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public Set<Address> getAddresses() {
        return addresses;
    }
    public void setAddresses(Set<Address> addresses) {
        this.addresses = addresses;
    }
}
//----------------------------------------------------------------------
//儿子
package org.crazy.app.domain;

import javax.persistence.*;

@Entity
@Table(name="address_inf")
public class Address {
    @Id
    @Column(name="address_id")
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer addressId;
    private String addressDetail;
    @ManyToOne(targetEntity=Person.class)
    @JoinColumn(name="person_id",referencedColumnName="person_id",nullable=false)
    private Person person;

    public Address(String addressDetail) {
        this.addressDetail = addressDetail;
    }
    public Integer getAddressId() {
        return addressId;
    }
    public void setAddressId(Integer addressId) {
        this.addressId = addressId;
    }
    public String getAddressDetail() {
        return addressDetail;
    }
    public void setAddressDetail(String addressDetail) {
        this.addressDetail = addressDetail;
    }
    public Person getPerson() {
        return person;
    }
    public void setPerson(Person person) {
        this.person = person;
    }

}

4，测试：

package lee;

import org.crazy.app.domain.Address;
import org.crazy.app.domain.Person;
import org.hibernate.Session;
import org.hibernate.Transaction;

public class PersonManager {
    public static void main(String[] args) {
        testCascase();
    }
    public static void testCascase(){
        Session session=HibernateUtil.currentSession();
        Transaction tx=session.beginTransaction();
        Person p=new Person();
        p.setAge(33);p.setName("abc");
        session.save(p);
        Address a=new Address("广州天河");
        a.setPerson(p);
        session.persist(a);
        Address a2=new Address("上海虹口");
        a2.setPerson(p);
        session.persist(a2);
        tx.commit();
        HibernateUtil.closeSession();
    }

}

5，运行，生成表结构 如下