这里的代码和我想要实现的是在删除时从注册表中删除注册对象。当我删除时，我想删除它在certificateChosen表中的相应证书值（其中包含主键id（来自注册）和cid（来自证书）和地址对象。
Registration.hbm.xml
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.global.manager.Registration" table="registrations">
<meta attribute="class-description">
This class contains the employee detail.
</meta>
<id name="id" type="int" column="id">
<generator class="native" />
</id>
<property name="username" column="username" type="string" />
<property name="password" column="password" type="string" />
<property name="dob" column="dob" type="string" />
<property name="email" column="email" type="string" />
<property name="phone" column="phone" type="string" />
<property name="registered" column="registered" type="string" />
<set name="certifications" table="certificatesChosen" cascade="all">
<key column="id" not-null="true" />
<many-to-many column="certificationId" class="com.global.manager.Certifications"
unique="true" />
</set>
<set name="address" table="address" cascade="all">
<key column="id" not-null="true" />
<one-to-many class="com.global.manager.Address" />
</set>
</class>
</hibernate-mapping>
Address.hbm.xml
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.global.manager.Address" table="address">
<meta attribute="class-description">
This class contains the courses opted by student
</meta>
<id name="aid" type="int" column="aid">
<generator class="native" />
</id>
<property name="type" column="type" type="string" />
<property name="street" column="street" type="string" />
<property name="city" column="city" type="string" />
<property name="state" column="state" type="string" />
<property name="country" column="country" type="string" />
<property name="pin" column="pin" type="int" />
<many-to-one name="registration" class="com.global.manager.Registration"
fetch="select" insert="false" update="false">
<column name="id" not-null="true" />
</many-to-one>
<!-- <many-to-one name="student" class="com.global.hibernate.Student" column="regnId"
not-null="true" /> -->
</class>
</hibernate-mapping>
Certifications.hbm.xml
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.global.manager.Certifications" table="certifications">
<meta attribute="class-description">
This class contains the courses opted by student
</meta>
<id name="cid" type="int" column="certificationId">
</id>
<property name="name" column="certificationName" type="string" />
<join table="certificatesChosen" inverse="true">
<key column="certificationId" />
<many-to-one name="registrations" column="id" not-null="true" />
</join>
</class>
</hibernate-mapping>
deleteUser.java（我实际上删除了一个注册对象）
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String username =request.getParameter("username");
DBHelper.deleteStudent(username);
}
DBHelper.java
public class DBHelper
{
public static void deleteStudent(String username) {
System.out.println("inside dbhelper");
try {
Configuration cfg = new Configuration().configure();
SessionFactory sf = cfg.buildSessionFactory();
Session session = sf.openSession();
Transaction tx = session.beginTransaction();
Criteria criteria = session.createCriteria(Registration.class).add(Restrictions.eq("username", new String(username)));
List <Registration> details = criteria.list();
session.delete(details.get(0));
tx.commit();
session.close();
}catch(HibernateException e) {
e.printStackTrace();
}
}
}
我从jsp页面发送用户名，执行时这是错误日志：
2017-12-15T18:46:01.902+0530|Severe: [http-thread-pool(5)] ERROR org.hibernate.util.JDBCExceptionReporter - Cannot delete or update a parent row: a foreign key constraint fails (`Jpa`.`certificatesChosen`, CONSTRAINT `certificatesChosen_ibfk_2` FOREIGN KEY (`certificationId`) REFERENCES `certifications` (`certificationId`))
2017-12-15T18:46:01.903+0530|Severe: [http-thread-pool(5)] ERROR org.hibernate.event.def.AbstractFlushingEventListener - Could not synchronize database state with session
2017-12-15T18:46:01.905+0530|Severe: org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:96)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275)
at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:114)
at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:109)
at org.hibernate.jdbc.AbstractBatcher.prepareBatchStatement(AbstractBatcher.java:244)
at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2650)
at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2895)
at org.hibernate.action.EntityDeleteAction.execute(EntityDeleteAction.java:97)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:268)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:260)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:184)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1206)
at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:375)
at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:137)
at com.global.manager.DBHelper.deleteStudent(DBHelper.java:90)
at com.global.manager.deleteUser.doGet(deleteUser.java:36)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1693)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:466)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:169)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:284)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:201)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:133)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:112)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:526)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:593)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:573)
at java.lang.Thread.run(Thread.java:748)
如果映射是正确的，请告诉我，如果它是在DBHelper中删除的一种方法。非常感谢你的帮助。谢谢！