many-to-many
第一种
就是定义两个实体对应数据库中的两张表，并且再定义一个中间实体对应数据库中的第三张表，用于维护两个实体间的多对多关联关系
１.Student.java
Java代码
packagecom.template.model;
importjava.util.List;
/**
*CreatedbyIntelliJIDEA.
*User:ZhongGang
*Date:11-7-20
*Time:下午9:31
*TochangethistemplateuseFile|Settings|FileTemplates.
*/
publicclassStudent{
privateIntegerid;
privateStringname;
privateList<Borrowed>borroweds;
publicStudent(){
}
}
２.Student.hbm.xml
Xml代码
<?xmlversion="1.0"?>
<!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mappingdefault-access="field">
<classname="com.template.model.Student"table="student">
<idname="id"column="id"type="java.lang.Integer">
<generatorclass="native"/>
</id>
<propertyname="name"column="name"type="java.lang.String"/>
<bagname="borroweds"table="borrowed">
<keycolumn="studentid"/>
<one-to-manyclass="com.template.model.Borrowed"/>
</bag>
</class>
</hibernate-mapping>
３.Book.java
Java代码
packagecom.template.model;
importjava.util.List;
/**
*CreatedbyIntelliJIDEA.
*User:ZhongGang
*Date:11-7-20
*Time:下午9:31
*TochangethistemplateuseFile|Settings|FileTemplates.
*/
publicclassBook{
privateIntegerid;
privateStringname;
privateList<Borrowed>borroweds;
publicBook(){
}
}
４.Book.hbm.xml
Xml代码
<?xmlversion="1.0"?>
<!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mappingdefault-access="field">
<classname="com.template.model.Book"table="book">
<idname="id"column="id"type="java.lang.Integer">
<generatorclass="native"/>
</id>
<propertyname="name"column="name"type="java.lang.String"/>
<bagname="borroweds"table="borrowed">
<keycolumn="bookid"/>
<one-to-manyclass="com.template.model.Borrowed"/>
</bag>
</class>
</hibernate-mapping>
５.Borrowed.java
Java代码
packagecom.template.model;
/**
*CreatedbyIntelliJIDEA.
*User:ZhongGang
*Date:11-7-20
*Time:下午9:31
*TochangethistemplateuseFile|Settings|FileTemplates.
*/
publicclassBorrowed{
privateIntegerid;
privateStudentstudent;
privateBookbook;
publicBorrowed(){
}
}
６.Borrowed.hbm.xml
Xml代码
<?xmlversion="1.0"?>
<!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mappingdefault-access="field">
<classname="com.template.model.Borrowed"table="borrowed">
<idname="id"column="id"type="java.lang.Integer">
<generatorclass="native"/>
</id>
<many-to-onename="book"class="com.template.model.Book"column="bookid"/>
<many-to-onename="student"class="com.template.model.Student"column="studentid"/>
</class>
</hibernate-mapping>
第二种
就是只定义两个实体对应数据库中的两张表，不需要定义第三个实体，而是在这两个实体中定义多对多的集合属性来维护这两个实体间的多对多关联关系
一。Concert.java
Java代码
packagecom.template.model.many;
importjava.util.List;
/**
*CreatedbyIntelliJIDEA.
*User:ZhongGang
*Date:11-7-30
*Time:下午4:56
*/
publicclassConcert{
privateIntegerid;
privateStringname;
privateStringsinger;
privateList<Venue>venues;
publicConcert(){
}
}
二。Concern.hbm.xml
Xml代码
<?xmlversion="1.0"encoding="UTF-8"?>
<!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mappingdefault-access="field">
<classname="com.template.model.many.Concert"table="concern"dynamic-insert="true"dynamic-update="true">
<idname="id"column="id"type="java.lang.Integer">
<generatorclass="native"/>
</id>
<propertyname="name"column="name"type="java.lang.String"/>
<propertyname="singer"column="singer"type="java.lang.String"/>
<bagname="venues"table="concern_venue">
<keycolumn="concernid"/>
<many-to-manyclass="com.template.model.many.Venue"column="venueid"/>
</bag>
</class>
</hibernate-mapping>
三。Venue.java
Java代码
packagecom.template.model.many;
importjava.util.List;
/**
*CreatedbyIntelliJIDEA.
*User:ZhongGang
*Date:11-7-30
*Time:下午4:56
*/
publicclassVenue{
privateIntegerid;
privateStringaddress;
privateList<Concert>concerts;
publicVenue(){
}
}
四。Venue.hbm.xml
Xml代码
<?xmlversion="1.0"encoding="UTF-8"?>
<!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mappingdefault-access="field">
<classname="com.template.model.many.Venue"table="venue"dynamic-insert="true"dynamic-update="true">
<idname="id"column="id"type="java.lang.Integer">
<generatorclass="native"/>
</id>
<propertyname="address"column="address"type="java.lang.String"/>
<bagname="concerts"table="concern_venue">
<keycolumn="venueid"/>
<many-to-manyclass="com.template.model.many.Concern"column="concernid"/>
</bag>
</class>
</hibernate-mapping>
看看数据库中的表结构吧
在第一种方法中，为中间实体也定义了一个Hibernate实体映射文件，使用的是one-to-many元素，而在第二种方法中则使用的是many-to-many元素。
一。Concert.java
Java代码
packagecom.template.model.many;
importjava.util.List;
/**
*CreatedbyIntelliJIDEA.
*User:ZhongGang
*Date:11-7-30
*Time:下午4:56
*/
publicclassConcert{
privateIntegerid;
privateStringname;
privateStringsinger;
privateList<Venue>venues;
publicConcert(){
}
}
二。Concern.hbm.xml
Xml代码
<?xmlversion="1.0"encoding="UTF-8"?>
<!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mappingdefault-access="field">
<classname="com.template.model.many.Concert"table="concern"dynamic-insert="true"dynamic-update="true">
<idname="id"column="id"type="java.lang.Integer">
<generatorclass="native"/>
</id>
<propertyname="name"column="name"type="java.lang.String"/>
<propertyname="singer"column="singer"type="java.lang.String"/>
<bagname="venues"table="concern_venue">
<keycolumn="concernid"/>
<many-to-manyclass="com.template.model.many.Venue"column="venueid"/>
</bag>
</class>
</hibernate-mapping>
三。Venue.java
Java代码
packagecom.template.model.many;
importjava.util.List;
/**
*CreatedbyIntelliJIDEA.
*User:ZhongGang
*Date:11-7-30
*Time:下午4:56
*/
publicclassVenue{
privateIntegerid;
privateStringaddress;
privateList<Concert>concerts;
publicVenue(){
}
}
四。Venue.hbm.xml
Xml代码
<?xmlversion="1.0"encoding="UTF-8"?>
<!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mappingdefault-access="field">
<classname="com.template.model.many.Venue"table="venue"dynamic-insert="true"dynamic-update="true">
<idname="id"column="id"type="java.lang.Integer">
<generatorclass="native"/>
</id>
<propertyname="address"column="address"type="java.lang.String"/>
<bagname="concerts"table="concern_venue">
<keycolumn="venueid"/>
<many-to-manyclass="com.template.model.many.Concern"column="concernid"/>
</bag>
</class>
</hibernate-mapping>
看看数据库中的表结构吧
在第一种方法中，为中间实体也定义了一个Hibernate实体映射文件，使用的是one-to-many元素，而在第二种方法中则使用的是many-to-many元素。