两种方式配置Hibernate复合主键(修正)

数据库结构

create table component(name varchar(50) not null,
sex varchar(50) not null,
description varchar(50),
primary key(name,sex));



主键类，一定要实现Serializable接口，并改写equals和hascode方法




package component;




import java.io.Serializable;




import org.apache.commons.lang.builder.EqualsBuilder;


import org.apache.commons.lang.builder.HashCodeBuilder;






public class ComponentPK implements Serializable ...{


private String name;


private String sex;






public String getName() ...{


return name;


}




public void setName(String name) ...{


this.name = name;


}




public String getSex() ...{


return sex;


}




public void setSex(String sex) ...{


this.sex = sex;


}




public boolean equals(Object obj) ...{




if(obj == this) ...{


return true;


}







if(!(obj instanceof Component)) ...{


return false;


}





ComponentPK componentpk = (ComponentPK) obj;


return new EqualsBuilder()


.append(this.name, componentpk.getName())


.append(this.sex, componentpk.getSex())


.isEquals();





}







public int hashCode() ...{


return new HashCodeBuilder()


.append(this.name)


.append(this.sex)


.toHashCode();


}




}








package component;






public class Component ...{


private String description;


private ComponentPK componentpk;




public ComponentPK getComponentpk() ...{


return componentpk;


}




public void setComponentpk(ComponentPK componentpk) ...{


this.componentpk = componentpk;


}




public String getDescription() ...{


return description;


}




public void setDescription(String description) ...{


this.description = description;


}


}





HBM文件




<?xml version="1.0" encoding="utf-8"?>


<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"


"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">


<!--


Mapping file autogenerated by MyEclipse - Hibernate Tools


-->


<hibernate-mapping package="component">




<class name="Component" table="component">


<composite-id name="componentpk"


class="ComponentPK"


unsaved-value="any">


<key-property name="name"


column="name"


type="java.lang.String"/>


<key-property name="sex"


column="sex"


type="java.lang.String"/>


</composite-id>





<property name="description" column="description" type="java.lang.String"/>





</class>




</hibernate-mapping>







测试代码：






public static void main(String[] args) ...{


Configuration cfg=new Configuration();


cfg.configure();


SessionFactory sf=cfg.buildSessionFactory();


Session session=sf.openSession();


Transaction t=session.beginTransaction();





ComponentPK pk=new ComponentPK();


pk.setName("1");


pk.setSex("3");





Component component=new Component();


component.setComponentpk(pk);


component.setDescription("12");


session.save(component);


t.commit();


System.out.println("success");




}





如果组成复合主键的某一个属性是其他持久话类的话，则需要使用<key many-to-one>

增加表User:

CREATE TABLE `user` (
`id` varchar(50) NOT NULL,
`pass` varchar(50) default NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=gb2312;

增加持久化类User及相应的Mapping文件




package component;






public class User ...{


private String id;


private String pass;




public String getId() ...{


return id;


}




public void setId(String id) ...{


this.id = id;


}




public String getPass() ...{


return pass;


}




public void setPass(String pass) ...{


this.pass = pass;


}


}




<?xml version="1.0" encoding="utf-8"?>


<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"


"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">


<!--


Mapping file autogenerated by MyEclipse - Hibernate Tools


-->


<hibernate-mapping package="component">




<class name="User" table="user">





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


<generator class="assigned"></generator>


</id>


<property name="pass" column="pass" type="java.lang.String"/>





</class>




</hibernate-mapping>



修改ComponentPK类




package component;




import java.io.Serializable;




import org.apache.commons.lang.builder.EqualsBuilder;


import org.apache.commons.lang.builder.HashCodeBuilder;






public class ComponentPK implements Serializable ...{


private String name;


private String sex;


private User user;




public User getUser() ...{


return user;


}




public void setUser(User user) ...{


this.user = user;


}




public String getName() ...{


return name;


}




public void setName(String name) ...{


this.name = name;


}




public String getSex() ...{


return sex;


}




public void setSex(String sex) ...{


this.sex = sex;


}




public boolean equals(Object obj) ...{




if(obj == this) ...{


return true;


}







if(!(obj instanceof Component)) ...{


return false;


}





ComponentPK componentpk = (ComponentPK) obj;


return new EqualsBuilder()


.append(this.name, componentpk.getName())


.append(this.sex, componentpk.getSex())


.isEquals();





}







public int hashCode() ...{


return new HashCodeBuilder()


.append(this.name)


.append(this.sex)


.toHashCode();


}




}



修改Component.hbm.xml


<hibernate-mapping package="component">




<class name="Component" table="component">


<composite-id name="componentpk"


class="ComponentPK"


unsaved-value="any">


<key-property name="name"


column="name"


type="java.lang.String"/>


<key-property name="sex"


column="sex"


type="java.lang.String"/>


<key-many-to-one name="user" class="User" column="userid" access="field" foreign-key="id"></key-many-to-one>


</composite-id>





<property name="description" column="description" type="java.lang.String"/>





</class>




</hibernate-mapping>

修改测试代码：






public static void main(String[] args) ...{


Configuration cfg=new Configuration();


cfg.configure();


SessionFactory sf=cfg.buildSessionFactory();


Session session=sf.openSession();


Transaction t=session.beginTransaction();





User user=(User)session.get(User.class, "11111");








ComponentPK pk=new ComponentPK();


pk.setName("1");


pk.setSex("3");


pk.setUser(user);





Component component=new Component();


component.setComponentpk(pk);





component.setDescription("12");


session.save(component);


t.commit();


System.out.println("success");




}

可以看到数据库结果如下：
User(id为111111)

id	pass
11111	!234

Component的联合主键(name,sex,userid),其中userid已经引用了user表的主键

name	sex	description	userid
1	3	12	11111