how to make onttomany relationship in spring hibernate
I am trying to relate two tables with spring / hibernate in MYSQL like this
@Table (name = candidatresumeinfo)
public class CandidateResumeInfo implements Serializable
{
List<SelectedResumes> selectedResumes;
......开发者_开发问答.......
..............
@JoinColumn(name = "selectedresumeid")
@OneToMany
public List<SelectedResumes> getSelectedResumes() {
return selectedResumes;
}
public void setSelectedResumes(List<SelectedResumes> selectedResumes) {
this.selectedResumes = selectedResumes;
}
Now ,i got the data in my list correctly( i checked in debug)but the call from server is getting failed which is saying cause:Nullpointer exception .
thanks
You can use OneToMany
annotation only on Collections, so you should change the field to Set or List, because hibernate will return multiple result if you use OneToMany. I think you'd like to use ManyToOne annotation here.
ManyToOne
means here that you have multiple CandidateResumeInfo for one SelectedResumes.OneToMany
means here that you have multiple SelectedResumes for one CandidateResumeInfo.
This annotation naming can be a bit strange for first time. Hope I helped.
Answer for your comment:
The best way is you declare the relationship both side. Here is the example:
CandidateResumeInfo.java:
@OneToMany(mappedBy="candidateResumeInfo")
List<SelectedResumes> selectedResumes;
SelectedResumes.java:
@ManyToOne
@JoinColumn(name="candidate_resume_info_id")
CandidateResumeInfo candidateResumeInfo;
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