Hibernate级联实践之三（many-to-many）

一。mapping

使用三个表，分别为TBL_OSU_PRODUCT_I、TBL_OSU_BUSINESSFUNCTION_I和TBL_OSU_PRODUCTBUSINESS_C，1和2为多对多关系，3为其中间表

1.TBL_OSU_PRODUCT_I

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

<!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN"

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

<hibernate-mapping>

<classname="com.netqin.function.osuproduct.product.model.OsuProduct"table="TBL_OSU_PRODUCT_I"schema="OSU_WORK">

<idname="id"type="long">

<columnname="PRDU_ID"precision="10"scale="0"/>

<generatorclass="sequence">

<paramname="sequence">SEQ_OSU_PRODUCT_I</param>

</generator>

</id>

<propertyname="prduName"type="string">

<columnname="PRDU_NAME"length="200"not-null="true"/>

</property>

<propertyname="prduDescription"type="string">

<columnname="PRDU_DESCRIPTION"length="200"/>

</property>

<setname="business"table="TBL_OSU_PRODUCTBUSINESS_C"lazy="false"inverse="false"cascade="save-update"schema="OSU_WORK">

<keycolumn="PRBU_PRDUID_FK"/>

<many-to-manyclass="com.netqin.function.osuproduct.businessfunction.model.BusinessFunction"column="PRBU_BUFUID_FK"/>

</set>

</class>

说明：只有1中做了关联配置。lazy="false" ：加载1时级联加载2，方便页面使用（看需要使用）。inverse="false"：控制权由1负责。

cascade="save-update" ：级联关系为新增和修改，不能加上delete，否则会一并删除2中的记录。

2.TBL_OSU_BUSINESSFUNCTION_I

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

<!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN"

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

<hibernate-mapping>

<classname="com.netqin.function.osuproduct.businessfunction.model.BusinessFunction"table="TBL_OSU_BUSINESSFUNCTION_I"schema="USERINFOV2">

<idname="bufuId"type="java.lang.String">

<columnname="BUFU_ID"length="10"/>

<generatorclass="uuid.hex"/>

</id>

<propertyname="bufuBusiidFk"type="java.lang.String">

<columnname="BUFU_BUSIID_FK"length="10"not-null="true"/>

</property>

<propertyname="bufuName"type="java.lang.String">

<columnname="BUFU_NAME"length="64"not-null="true"/>

</property>

<propertyname="bufuType"type="java.lang.Long">

<columnname="BUFU_TYPE"precision="4"scale="0"not-null="true"/>

</property>

</class>

说明：没有做关联

3.TBL_OSU_PRODUCTBUSINESS_C

没有映射文件，仅有两个字段，代表两个表的主键，分别为PRBU_PRDUID_FK和PRBU_BUFUID_FK，前者为1的主键，后者为2的主键

二。操作方法

1.新增

String[] businesses= request.getParameterValues("businesses");

if (businesses != null&& businesses.length > 0) {

for(inti=0;i<businesses.length;i++){

BusinessFunctionbf=(BusinessFunction)dao.findById(BusinessFunction.class,businesses[i]);//根据主键从数据库中查询出另一方的对象

object.getBusiness().add(bf);//关联对象

}

dao.save(object);

2.修改

OsuProduct object_tem = this.findById(object.getId());//从数据库中查询出主表对象

object_tem.getBusiness().removeAll(object_tem.getBusiness());//清空原有级联对象

copyProject(object_tem, object);//其余属性复制，同many-to-one

String[] businesses= request.getParameterValues("businesses");

if (businesses != null&& businesses.length > 0) {

for(inti=0;i<businesses.length;i++){

BusinessFunctionbf=(BusinessFunction)dao.findById(BusinessFunction.class,businesses[i]);

object_tem.getBusiness().add(bf);

}

dao.update(object_tem);

3.删除

删除主表即可

dao.delete(object);