hibernate 复合主键 多对多 级联保存

package com.patsnap.hibernate.beans;

import java.io.Serializable;
import java.util.List;

public class Patent implements Serializable{
?private String pn;
?
?private String apno;
?
?private List<LegalStatus> legalStatus;
?
?public List<LegalStatus> getLegalStatus() {
??return legalStatus;
?}
?public void setLegalStatus(List<LegalStatus> legalStatus) {
??this.legalStatus = legalStatus;
?}
?public String getPn() {
??return pn;
?}
?public void setPn(String pn) {
??this.pn = pn;
?}
?public String getApno() {
??return apno;
?}
?public void setApno(String apno) {
??this.apno = apno;
?}
}

?

package com.patsnap.hibernate.beans;

import java.util.List;

public class LegalStatus {
?private int id;
?
?private String apno;
?
?private List<Patent> patents;

?public List<Patent> getPatents() {
??return patents;
?}

?public void setPatents(List<Patent> patents) {
??this.patents = patents;
?}

?public int getId() {
??return id;
?}

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

?public String getApno() {
??return apno;
?}

?public void setApno(String apno) {
??this.apno = apno;
?}
}

?

<?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" >
<hibernate-mapping package="com.patsnap.hibernate.beans">
?<class name="Patent" table="Patent">
??<composite-id>
???<key-property name="pn" type="string" column="pn" />
???<key-property name="apno" type="string" column="apno" />
??</composite-id>

??<bag name="legalStatus" table="Patent_LegatStatus"
???inverse="false">
???<key>
????<column name="pn"></column>
????<column name="apno"></column>
???</key>
???<many-to-many column="id" />
??</bag>
?</class>
</hibernate-mapping>??

?

<?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" >
<hibernate-mapping package="com.patsnap.hibernate.beans">
?<class name="LegalStatus" table="LegalStatus">
??<id name="id" column="id" type="int">
???<generator />
??</id>
??<property name="apno" column="apno" type="java.lang.String" />

??<bag name="patents" table="Patent_LegatStatus"
???inverse="false">
???<key>
????<column name="id"></column>
???</key>
???<many-to-many class="Patent">
????<column name="pn"></column>
????<column name="apno"></column>
???</many-to-many>
??</bag>
?</class>
</hibernate-mapping>??

?

?

注1：这里bag标签里没有设置cascade属性，这样在保存Patent或LegalStatus时仅级联保存中间表，不会删除中间表数据，但要求保存一方的时候，另一方的数据必须已经存在（因为仅级联保存中间表数据，不会保存另一方数据）

public static void insert() {
??Session session = HibernateSessionFactory.getSession();
??Transaction t = session.beginTransaction();

??LegalStatus legalStatus = new LegalStatus();
??legalStatus.setApno("12345");

??Patent patent = new Patent();
??patent.setPn("321141112");
??patent.setApno("3211112");//该patent在数据库必须已经存在，否则报错
??List<Patent> list = new ArrayList<Patent>();
??list.add(patent);
??legalStatus.setPatents(list);

??session.save(legalStatus);

??t.commit();

?}

注2：如果bag标签里cascade属性设置了相应值（如save-update等），则在保存一方数据的同时会保存同时保存中间表和另一方的数据（如果不存在的话），但是再保存两者关系的同时，会先把中间表数据删除一遍，再加上当前添加的关系，所以这时候要特别注意，要先把关系设置完整再做保存操作，否则会删除已有的关系

public static void insert(){
??? ?Session session = HibernateSessionFactory.getSession();
??? ?Transaction t = session.beginTransaction();
??? ?
??? ?
??? ?LegalStatus legalStatus =new LegalStatus();
??? ?legalStatus.setApno("12345");
??? ?
??? ?
??? ?List<Patent> patentList = session.createQuery("from Patent where pn ='321141112' and apno='3211112'").list();
??? ?Patent patent = new Patent();
??? ?if (patentList.size()==1) {
??? ??patent = patentList.get(0);
??? ??patent.getLegalStatus().add(legalStatus);//保证原有的关系不变，不做这一步则丢失原有关系
??}else {
???patent.setPn("321141112");
???patent.setApno("3211112");
???List<Patent> list = new ArrayList<Patent>();
???list.add(patent);
???legalStatus.setPatents(list);
??}
?????????
?????session.save(legalStatus);
??? ?
??? ?t.commit();
??? ?
??? }

注3：如果涉及到复合主键，该类需要implements Serializable