Hibernate中联合主键的配置

Hibernate中联合主键的配置

今天一个同事问起了我一个问题，就是Hibernate中联合主键怎么配置，由于以前没用过联合主键，而且公司上班没有外网，所以无法查找相关资料。晚上回来了，自己找找了些资料。解决了联合主键的问题。首先给出问题的背景吧：有三个对象，即Course（课程对象）、Trainee(公司被训练的新人)、Feedback（trainee对某门课程的反馈）。对应这数据库中三张表：tab_course(course_id,name)、tab_trainee(trainee_id,name,)、tab_trainee_course(trainee_id,course_id,feedbackDetail)，其中tab_trainee_course需要用tab_trainee和tab_course的主键联合当作主键。

新建一个TraineeAndCourse对象

package com.clark.model;

import java.io.Serializable;

public class TraineeAndCourse implements Serializable{

private static final long serialVersionUID = -8073048353348932152L;

private int traineeId;

private int courseId;

private String feedbackDetail;

public TraineeAndCourse(){

}

public int getTraineeId() {

return traineeId;

}

public void setTraineeId(int traineeId) {

this.traineeId = traineeId;

}

public int getCourseId() {

return courseId;

}

public void setCourseId(int courseId) {

this.courseId = courseId;

}

public String getFeedbackDetail() {

return feedbackDetail;

}

public void setFeedbackDetail(String feedbackDetail) {

this.feedbackDetail = feedbackDetail;

}

public static long getSerialversionuid() {

return serialVersionUID;

}

public TraineeAndCourse(int traineeId, int courseId, String feedbackDetail) {

super();

this.traineeId = traineeId;

this.courseId = courseId;

this.feedbackDetail = feedbackDetail;

}

}

对应的traineeAndcourse.hbm.xml配置文件如下

<?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 Persistence Tools

-->

<hibernate-mapping package="com.clark.model">

<class name="TraineeAndCourse" table="tab_trainee_course" catalog="hibernate">

<!-- 联合主键的配置 -->

<composite-id>

<key-property name="traineeId" type="int">

<column name="trainee_id" length="10"></column>

</key-property>

<key-property name="courseId" type="int">

<column name="course_id" length="10"></column>

</key-property>

</composite-id>

<property name="feedbackDetail" type="java.lang.String">

<column name="feedback_detail" />

</property>

</class>

</hibernate-mapping>

对应的测试dao为

package com.clark.dao;

import org.hibernate.Session;

import org.hibernate.Transaction;

import com.clark.model.Course;

import com.clark.model.Trainee;

import com.clark.model.TraineeAndCourse;

import com.clark.session.HibernateSessionFactory;

public class TraineeAndCourseDao {

public Session session=HibernateSessionFactory.getSession();

public void save(){

Transaction tx=session.beginTransaction();

TraineeAndCourse tac=new TraineeAndCourse();

tac.setTraineeId(1);

tac.setCourseId(2);

tac.setFeedbackDetail("问卷调查");

session.save(tac);

tx.commit();

session.close();

}

public static void main(String[] args) {

new TraineeAndCourseDao().save();

}

}