Java Hibernate在复合主键中保存具有父外键的唯一子表项

我是Hibernate&Spring MVC的初学者，正在努力找到问题的正确解决方案。 我有父表（事件）和子表（投票）。每当从URL接收到数据时，我想保存唯一的子表条目。我在映射关系和使用复合键时遇到问题

以下是我的结构：

create table Events(
Event_ID int(11) NOT NULL AUTO_INCREMENT,
Event_Name varchar(200) NOT NULL,
Event_options int(1) NOT NULL,
Start_TIME timestamp,
End_time   timestamp,
Active_Status int(1),
PRIMARY KEY(Event_ID)
)ENGINE=InnoDB AUTO_INCREMENT=16
;

create table Votes(
Event_ID int(11) NOT NULL,
Voter_MSISDN int(13) NOT NULL,
Vote_Option int(1),
PRIMARY KEY(Event_ID,Voter_MSISDN),
FOREIGN KEY (Event_ID) REFERENCES Events(Event_ID)
)ENGINE=InnoDB AUTO_INCREMENT=16
;

Events.java

@Entity
@Table(name="Events")
public class Events {

    @Id
    @GeneratedValue
    @Column(name = "Event_ID")
    private Integer eventId;

    @Column(name="Event_Name")
    private String eventName;

    @Column(name="Event_options")
    private Integer eventOptions;

    @Column(name="Start_TIME")
    private String startTime;

    @Column(name = "End_time")
    private String End_time;

    @Column(name="Active")
    private Integer status;

    @OneToMany(mappedBy = "Events")
    private Set<Votes> votes;
     //Setter Getters

}

通过@embeddeble为复合主键设置Vote.java

@Embeddable
public class Vote implements Serializable{

        public Vote(){}

        @Column(name="Event_ID")
        private int Event_ID;

        @Column(name="Voter_MSISDN")
        private long Voter_MSISDN;

        //setter getters
}

用于添加事件和添加投票的控制器代码段

@RequestMapping(value="/AddEvent")
    @ResponseStatus(value = HttpStatus.OK)
    public void AddEvent(@RequestParam(value = "ename", required = true) String ename, 
                        @RequestParam (value = "opt") String opt, 
                        @RequestParam (value = "stime") String start,
                        @RequestParam (value = "etime") String end,
                        @RequestParam (value = "status") String active){

        Events event = new Events();
        event.setEventName(ename);
        event.setEventOptions(Integer.parseInt(opt));
        event.setStartTime(start);
        event.setEnd_time(end);
        event.setStatus(Integer.parseInt(active));

        userDao.saveEvent(event);
    }

    @Autowired
    private Vote vote;

    @Autowired
    private Votes votes;

    @RequestMapping(value="/AddVote")
    @ResponseStatus(value = HttpStatus.OK)
    public void AddVote(@RequestParam(value = "eventid",required = true) String eventid,
                        @RequestParam(value="msisdn") String msisdn,
                        @RequestParam(value = "opt")String opt){

        logger.info("Received parameters from URL "+eventid+" "+msisdn+" "+opt);
        vote.setEvent_ID(Integer.parseInt(eventid));


        vote.setVoter_MSISDN(Long.parseLong(msisdn));

        votes.setVote(vote);
        votes.setVote_Option(Integer.parseInt(opt));

        userDao.saveVotes(votes);           
    }
}

实施：

@Transactional
    public void saveEvent(Events event) {
        // TODO Auto-generated method stub
        Session session = sessionFactory.getCurrentSession();

        session.save(event);

    }

    @Transactional 
    public void saveVotes(Votes votes){

        Session session = sessionFactory.getCurrentSession();

        session.save(votes);
    }

只要接收到事件数据并添加了事件条目，代码就可以正常工作。 无法为投票数据正确编码。 每当从url接收到投票数据时，我只想插入投票数据。我添加了复合主键，以确保来自一个用户（MSISDN）的每个事件的唯一条目。 请建议此模型的正确映射。

---

欢迎提出任何改进建议

首先，对于这个简单的解决方案，您不需要复合密钥

你有一门课：

@Entity
@Table(name="Events")
public class Events {

    //....................

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "Events")
    private Set<Votes> votes = new HashSet<>();

}

然后在addVote控制器方法中：

@RequestMapping(value="/AddVote")
@ResponseStatus(value = HttpStatus.OK)
public void AddVote(@RequestParam(value = "eventid",required = true) String eventid,
                    @RequestParam(value="msisdn") String msisdn,
                    @RequestParam(value = "opt")String opt){

    Event event = userDao.findEvent(eventid);
    Vote vote = event.createVote(); //This will create a vote for an event.

    vote.set.... //set your stuff.
    //It will cascade your vote to an event if you have a cascade sorted correctly as in the example above: cascade = CascadeType.ALL
}

确保你的交易是正确的。这只是一个应该怎么做的想法

public Vote createVote() {
    Vote vote = new Vote();
    vote.setEvent(this);
    votes.add(vote);
    return vote;
}

@RequestMapping(value="/AddVote")
@ResponseStatus(value = HttpStatus.OK)
public void AddVote(@RequestParam(value = "eventid",required = true) String eventid,
                    @RequestParam(value="msisdn") String msisdn,
                    @RequestParam(value = "opt")String opt){

    Event event = userDao.findEvent(eventid);
    Vote vote = event.createVote(); //This will create a vote for an event.

    vote.set.... //set your stuff.
    //It will cascade your vote to an event if you have a cascade sorted correctly as in the example above: cascade = CascadeType.ALL
}