I want to load all objects from a table without a lazy objects/children and list them on the page (Thymeleaf template), but I get a LazyInitializationException every time. I tried to convert Hibernate entity objects into a POJO that doesnt contains a lazy/unwanted object but with the same result. I also tried open-in-view parameter set to false...
Simple example:
Parent:
@Entity
public class DocumentDbe implements Serializable {
public DocumentDbe(){
}
@Id
@Column(name = "id", updatable = false, nullable = false)
private Long id;
@OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
private DocumentFileDbe documentFile;
....
}
Child:
@Entity
public class DocumentFileDbe implements Serializable {
public DocumentFileDbe(){}
@Id
@Column(name = "id", updatable = false, nullable = false)
private Long id;
@Column
@Lob
private byte[] documentData;
...
}
POJO:
public class DocumentDto implements Serializable {
public DocumentDto(){
}
public DocumentDto(DocumentDbe doc){
this.id = doc.getId();
}
....
}
Controller:
@GetMapping("/list")
String getList(Model model) {
List<DocumentDbe> docs;
List<DocumentDto> data = new ArrayList<>();
try (Session ses = sessionFactory.openSession()) {
docs = ses.createQuery("FROM DocumentDbe").list();
docs.forEach(doc -> {
data.add(new DocumentDto(doc));
});
}
model.addAttribute(MODEL_LIST_DATA, data);
return "list";
}
EDIT: Thrown exception:
org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/list.html]")] with root cause
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
EDIT2:
In DocumentDbe is relation with another object (EAGER this time so I was not paying attention to it) , which has reference to DocumentDbe again.. chained relationship and LazyInitializationException is created...
EDIT3:
Although
This is modified and working controller, without POJO:
@GetMapping("/list")
String getList(Model model) {
List<DocumentDbe> docs;
try (Session ses = sessionFactory.openSession()) {
docs = ses.createQuery("FROM DocumentDbe ORDER BY id DESC").list();
docs.forEach(doc -> {
doc.setDocumentFile(null);
doc.getHistory().forEach(log ->{
log.setDocument(null);
});
});
}
model.addAttribute(MODEL_ADMIN_DATA, docs);
return "list";
}
