hibernate 映射关系（快速原型）_1-阿里云开发者社区

此方法在快速建立项目原型上有很大帮助（这最关键的就是速度，用的好原型很快就能建立起来）
先确定下“快速原型”环境定义：
使用：ant+hibernate_xdoclet+hibernate_create_table
过程：定义bean(xdoclet) -> hbm映射文件 -> hibernate.hbm2ddl.auto create -> 逻辑
注意：如有使用泛型，请使用 > xjavadoc-1.1.jar
build.xml

<? xml version="1.0" encoding="UTF-8" ?>
< project >
     < property file ="build-dist.properties" />

     < path id ="class.path" >
         < fileset dir ="${ant.lib.dir}" >
             < include name ="*.jar" />
         </ fileset >
         < fileset dir ="${project.lib.dir}" >
             < include name ="*.jar" />
         </ fileset >
     </ path >

     
     
     
     < target name ="init" >
         < taskdef name ="hibernatedoclet" classname ="xdoclet.modules.hibernate.HibernateDocletTask" classpathref ="class.path" />
     </ target >

     
     
     
     < target name ="hibernate" depends ="init" >

         < echo > +---------------------------------------------------+ </ echo >
         < echo > |                                                   | </ echo >
         < echo > | R U N N I N G   H I B E R N A T E D O C L E T     | </ echo >
         < echo > |                                                   | </ echo >
         < echo > +---------------------------------------------------+ </ echo >

         < hibernatedoclet destdir ="${config.dir}" mergedir ="${config.dir}" excludedtags ="@version,@author,@todo,@see" addedtags ="@xdoclet-generated at ${TODAY},@copyright The XDoclet Team,@author XDoclet,@version ${version}" force ="${samples.xdoclet.force}" verbose ="false" >
             < fileset dir ="${src.dir}" >
                 < include name ="bean/**/*.java" />
             </ fileset >
             < hibernate version ="3.0" />
         </ hibernatedoclet >

     </ target >

</ project >

ant配置文件

# 当然根据你自己的项目路径
ant.lib.dir = C:\\src\\test\\hbmTest\\action\\lib
project.lib.dir = C:\\src\\test\\hbmTest\\lib
src.dir = C:\\src\\test\\hbmTest\\src
config.dir = C:\\src\\test\\hbmTest\\config

hibernate.hbm.xml

<? 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 >
         < property name ="hibernate.connection.driver_class" > org.gjt.mm.mysql.Driver </ property >
         < property name ="connection.url" >
             <![CDATA[
            jdbc:mysql://localhost:3306/hbm?characterEncoding=utf8&connectionCollation=gbk_chinese_ci
             ]]>
         </ property >
         < property name ="hibernate.connection.username" > root </ property >
         < property name ="hibernate.dialect" > org.hibernate.dialect.MySQLDialect </ property >
         < property name ="hibernate.connection.password" >****** </ property >
         <property name="hibernate.hbm2ddl.auto">create</property>
         < property name ="hibernate.show_sql" > true </ property >
        
         < mapping resource ="bean\unidirectional\m2o\Person.hbm.xml" />
         < mapping resource ="bean\unidirectional\m2o\Address.hbm.xml" />

     </ session-factory >
</ hibernate-configuration >

下面就详细介绍了第一个
单项一对多
1.先定义bean

package bean.unidirectional.m2o;
/**
* @hibernate.class
*/
public class Person {
     private int id;
     private Address address;

     /**
     * @hibernate.id generator-class = "native"
      */
     public int getId() {
         return id;
    }

     public void setId( int id) {
         this .id = id;
    }

     /**
     * @hibernate.many-to-one column = "addressId" not-null = "true"
      */
     public Address getAddress() {
         return address;
    }

     public void setAddress(Address address) {
         this .address = address;
    }
}

package bean.unidirectional.m2o;

/**
* @hibernate.class
*/
public class Address {
     private int id;

     /**
     * @hibernate.id generator-class = "native"
      */
     public int getId() {
         return id;
    }

     public void setId( int id) {
         this .id = id;
    }

}

2.运行 ant hibernate 得到 hbm 映射文件
3.Main 运行测试

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;

import util.HibernateUtil;
import bean.unidirectional.m2o.Address;
import bean.unidirectional.m2o.Person;

public class Main {
     public static void main(String[] args) {
        Session session1 = HibernateUtil.currentSession();
        Transaction t1 = session1.beginTransaction();
         // insert
        Address address1 = new Address();
        Address address2 = new Address();

        Person person1 = new Person();
        Person person2 = new Person();
            person1.setAddress(address1);
            person2.setAddress(address1);
        Person person3 = new Person();
        person3.setAddress(address2);

        session1.save(address1);
        session1.save(address2);
        session1.save(person1);
        session1.save(person2);
        session1.save(person3);
        t1.commit();

         // 查询有重复的 address
        Session session2 = HibernateUtil.currentSession();
        Query query = session2.createQuery(
                 " select ta from " +
                    Address. class .getName() + " ta , " +
                    Person. class .getName() + " tp " +
                 " where ta.id=tp.address " +
                 " group by ta.id having count(ta.id)>1 "
        );

        List < Address > list =   query.list();
         for (Address atmp : list ){
            System.out.println( atmp.getId() );
        }
    }
}

数据库：
mysql> show tables ;
+-----------------------+
| Tables_in_hbm |
+-----------------------+
| address |
| person |
+-----------------------+
结果：
Hibernate: insert into Address values ( )
Hibernate: insert into Address values ( )
Hibernate: insert into Person (addressId) values (?)
Hibernate: insert into Person (addressId) values (?)
Hibernate: insert into Person (addressId) values (?)
Hibernate: select address0_.id as id from Address address0_, Person person1_ where address0_.id=person1_.addressId group by address0_.id having count(address0_.id)>1
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当然我这文章主要是映射关系，下面我们就进主题，大家想尝试下可以使用上面的原型快速测试：参考（在此我对参考加入了自己的注解，希望能给大家帮助。对于在实际开发中不常见或难以实现的我们就不介绍了）

单向一对一（one to one）

#通过外键关联

<class name="Person">
<id name="id" column="personId">
<generator class="native"/>
</id>
<many-to-one name="address" 
column="addressId" 
unique="true"
not-null="true"/>
</class>

<class name="Address">


<id name="id" column="addressId">

<generator class="native"/>

</id>

</class>

create table Person ( personId bigint not null primary key, addressId bigint not null unique )

create table Address ( addressId bigint not null primary key )

#通过主键关联（请注意，例子中掉换了关联的方向）
<class name = " Person " >
    <id name = " id " column = " personId " >
        <generator class = " native " />
    </id>
</class>

<class name = " Address " >
    <id name = " id " column = " personId " >
        <generator class ="foreign">
            <param name="property" >person</param>
        </generator>
    </id>
    <one-to-one name = " person " constrained = " true " />
</class>

create table Person ( personId bigint not null primary key )
create table Address ( personId bigint not null primary key )

单向一对多（one to many）

<class name = " Person " >
    <id name = " id " column = " personId " >
        <generator class = " native " />
    </id>
    <set name ="addresses">
        <key column="personId" not-null="true"/>
        <one-to-many class="Address" />
    </set>
</class>

<class name = " Address " >
    <id name = " id " column = " addressId " >
        <generator class = " native " />
    </id>
</class>

create table Person ( personId bigint not null primary key )
create table Address ( addressId bigint not null primary key , personId bigint not null

# 这里当 ddl主键对象会多出 n条被外键对象的 update
# 解决办法修改映射为双向，并且 set-inverse = "false"并且在代码中‘孩子.set父亲()’和 ‘ 父亲 .add 孩子 () ’ 一定要写明
# 如果不希望硬代码就 set- inverse ="true" ‘ 父亲 .add 孩子 () ’在生成sql 中就会有多余的update
# 当然根据逻辑情况来选择

/**
* @hibernate.class
*
*/
public class Person {
     private int id;
     private Set < Address > addresss;

     /**
     * @hibernate.id
     *   generator-class = "native"
     * @return
      */
     public int getId() {
         return id;
    }

     public void setId( int id) {
         this .id = id;
    }

     /**
     * @hibernate.set inverse = "false"
     *     @hibernate.collection-key column ="personId"
     *  @hibernate.collection-one-to-many class = "bean.unidirectional.m2o.Address"
      */
     public Set < Address > getAddresss() {
         return addresss;
    }

     public void setAddresss(Set < Address > addresss) {
         this .addresss = addresss;
    }

}

/**
* @hibernate.class
* @author root
*
*/
public class Address {
     private int id;
     private Person person ;

     /**
     * @hibernate.id generator-class = "native"
      */
     public int getId() {
         return id;
    }

     public void setId( int id) {
         this .id = id;
    }
     /**
     * @hibernate.many-to-one
     *     column = "personId"
     * @return
      */
     public Person getPerson() {
         return person;
    }

     public void setPerson(Person person) {
         this .person = person;
    }


}
     public static void main(String[] args) {
        Session session1 = HibernateUtil.currentSession();
        Transaction t1 = session1.beginTransaction();
         // insert
        Address address1 = new Address();
        Address address2 = new Address();
        Set < Address > addresss = new HashSet < Address > ();
        addresss.add(address1);
        addresss.add(address2);

        Person person1 = new Person();
            person1.setAddresss(addresss);

        address1.setPerson(person1);
        address2.setPerson(person1);

        session1.save(person1);
        session1.save(address1);
        session1.save(address2);

        t1.commit();

         // 查询有重复的 address
        Session session2 = HibernateUtil.currentSession();
        Query query = session2.createQuery(
                 "   from " + Person. class .getName() + " tp "
        );

        List < Person > list =   query.list();
         for (Person ptmp : list ){
             for ( Address atmp : ptmp.getAddresss() ){
                System.out.println(atmp.getId());
            }
        }

结果： 干净的 insert

Hibernate: insert into Person values ( )
Hibernate: insert into Address values ( )
Hibernate: insert into Address values ( )
Hibernate: select person0_.id as id from Person person0_
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