hibernate如何保存一对多/多对一的注释？(孩子们没有保存)

Question

我继承了一个hibernate应用程序,但我遇到了问题.似乎代码不会将孩子保存为一对多关系.它是双向的,但是在保存父对象时,它似乎不会保存孩子.

在这种情况下,Question类是父类.

// Question.java
@Entity
@SequenceGenerator(name = "question_sequence", sequenceName = "seq_question", allocationSize = 1000)
@Table(name = "question")
public class Question {
   protected Long questionId;
   protected Set<AnswerValue> answerValues;

   public TurkQuestion(){}

   public TurkQuestion(Long questionId){
      this.questionId = questionId;
   }

   @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "question_sequence")
   @Column(name = "question_id")
   public Long getQuestionId(){
      return questionId;
   }

   @OneToMany(fetch = FetchType.EAGER)
   @JoinColumn(name = "question_id",referencedColumnName="question_id")
   public Set<AnswerValue> getAnswerValues(){
      return answerValues;
   }

   public void setQuestionId(Long questionId){
      this.questionId = questionId;
   }

   public void setAnswerValues(Set<AnswerValue> answerValues){
      this.answerValues = answerValues;
   }
}

AnswerValue是子类.

// AnswerValue.java
@Entity
@SequenceGenerator(name = "answer_value_sequence", sequenceName = "seq_answer_value", allocationSize = 1)
@Table(name = "answer_value")
public class AnswerValue {
    protected Long answerValueId;
    protected Question question;
    protected String answerValue;

    public AnswerValue(){}

    public AnswerValue(Long answerValueId, Long questionId, String answerValue){
       this.answerValueId = answerValueId;
       this.question = new Question(questionId);
       this.answerValue = answerValue;
    }

    @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "answer_value_sequence")
    @Column(name = "answer_value_id")
    public Long getAnswerValueId(){
       return answerValueId;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "question_id", nullable = false )
    public Question getQuestion(){
       return question;
    }

    @Column(name = "answer_value")
    public String getAnswerValue(){
       return answerValue;
    }

    public void setAnswerValueId(Long answerValueId){
       this.answerValueId = answerValueId;
    }

    public void setQuestion(Question question){
       this.question = question;
    }

    public void setAnswerValue(){
       this.answerValue = answerValue;
    }
}

和DAO:

// QuestionDao.java
public class QuestionDao {
   public void saveOrUpdateAll(List<Question> list){
      getHibernateTemplate().saveOrUpdateAll(list);
   }
}

当我调用saveOrUpdateAll时,似乎保存了Question,但是Question对象的子元素AnswerValue却没有.

有什么建议？

Answer 1

你需要手动完成它或者将cascade属性添加到你的注释中,即Hibernate:Cascade Type

或者Hibernate:如何在注释中使用级联？

Answer 2

对于oneToMany关系,请将cascade映射注释定义为:

    Cascade={CascadeType.ALL}

要么

     Cascade={ CascadeType.ALL, CascadeType.DELETE_ORPHAN }

在您的映射中:

    @ManyToOne(fetch = FetchType.EAGER, 
               cascade = { CascadeType.ALL, CascadeType.DELETE_ORPHAN })
    @JoinColumn(name = "question_id",referencedColumnName="question_id")
    public Set<AnswerValue> getAnswerValues(){
        return answerValues;
    }