In my spring JPA project I have two entities, Task and Developer. List can assign to a Developer and one Task can have just one Developer. I mapped them:
Developer
#Entity
#Table(name = "DEVELOPER")
public class Developer implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
#OneToMany(targetEntity = Task.class , mappedBy = "developer",cascade=CascadeType.ALL, fetch = FetchType.LAZY)
private List<Task> taskList;
Task
#Entity
#Table(name = "TASK")
public class Task implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long taskId;
private String taskTitle;
#ManyToOne
#JoinColumn(name="developer_id")
private Developer developer;
When I assign a List of Task to a Developer, JSON format is:
{
"id": 1,
"name": "John",
"taskList": [
{
"taskId":2,
"taskTitle": "Do sth"
}
]
}
But the value of Developer in above Task object is null:
{
"taskId":2,
"taskTitle": "Do sth",
"developer": null
}
I expect to this developer property is not null and Developer and task have a bidirectional relationship.
How can I solve this? I am new in Spring and Hibernate. Any help would be greatly appreciated.
might missing cascade=CascadeType.ALL in #ManyToOne annotation, and in Java doc, it says : (Optional) The operations that must be cascaded to the target of the association.By default no operations are cascaded.， https://docs.jboss.org/hibernate/jpa/2.1/api/javax/persistence/ManyToOne.html
Remove cascade=CascadeType.ALL in Developer class and add #joinColumn annotation, it will work.
Developer class will look like this-
#Entity
#Table(name = "DEVELOPER")
public class Developer implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
#OneToMany(targetEntity = Task.class , mappedBy = "developer", fetch = FetchType.LAZY)
#JoinColumn(name="task_developer_id")
private List<Task> taskList;
Related
I have two entities with one-to-mane relationship:
#Entity
public class User implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id", nullable = false)
private Long id;
#OneToMany(mappedBy = "user", cascade = CascadeType.ALL)
#JsonManagedReference
private List<RealEstate> realEstates = new ArrayList<>();
#Entity
public class RealEstate implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private Long id;
private String name;
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "user_id")
#JsonBackReference
private User user;
I try to save realEstate entity with this code:
realEstate.setUser(user);
realEstateService.saveRealEstate(realEstate);
And this response:
[
{
"id": 1,
"name" : "Bueno",
"user" : 1
}
]
By all I have is creating new record in user table and relation with this new ID.
What I do wrong? What I need to read about this?
You first need to save User entity record and then RealEstate entity record.
Please read this article to implement One To Many relationship. I am sure your issue will be resolved.
https://attacomsian.com/blog/spring-data-jpa-one-to-many-mapping
I have a user entity:
#Entity(name = "users")
#DynamicUpdate
public class User implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#OneToMany(mappedBy = "user", cascade = CascadeType.ALL)
#JsonIgnore
#JsonIgnoreProperties("user")
private Set<Car> cars;
}
and a car entity:
#Entity(name = "cars")
#DynamicUpdate
public class Car implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Column(name = "plate_number")
#JsonView(View.Summary.class)
private String plateNumber;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name="user_id")
#JsonIgnore
#JsonManagedReference("user-coordinate")
#Access(value = AccessType.FIELD)
private User user;
}
when I get cars list I get this:
{
"id": 5,
"plateNumber": "aaaaada",
"user": {
"id": 110,
"name": null
}
},
But I want to get this(without user entity!):
{
"id": 5,
"plateNumber": "aaaaada",
},
I have 7 years' experience in PHP (I said it to know I am familiar with how to search and get what I want) but I am a beginner in java spring I searched a lot for the answer all I get is that it's related to Jackson but I don't know how to solve it please help me with details I will appreciate it.
Thank you
you are using #JsonManagedReference("user-coordinate") which overrides #JsonIgnore
JsonManagedReference directs Jackson to serialize the user when serializing car, so if you want user to not be serialized you need to removed it so #JsonIgnore takes place
For anyone had this problem two, I had two dependencies for JsonIgnore I was using:
org.codehaus.jackson.annotate
that was the problem I changed it to:
com.fasterxml.jackson.annotation
And the problem solved
I just do not want to do:
myEntity = findById(Long id)
findAllByEntityAnd*(MyEntity myEntity, *)
instead I want do:
findAllByEntityAnd*(Long entityId, *)
Is there something I missed to achieve what I wanted or I just cannot achieve it directly?
Thanks for the help ~
When I tried it, the Spring prompted me:
java.lang.IllegalArgumentException: Could not create query metamodel for method public abstract java.util.List com.worksap.morphling.raptor.dump.thread.dao.ThreadDoRepository.findAllByDumpDoAndLocksWaitingContains(java.lang.Long,java.lang.String)!
Here is my table for your reference:
#Data
#Builder
#Entity
#Table(name = "thread_info")
#AllArgsConstructor
#NoArgsConstructor
public class ThreadDo implements Serializable {
private static final long serialVersionUID = -1L;
String name;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#ManyToOne
#JoinColumn(name = "thread_dump_id")
#JsonIgnore
private ThreadDumpDo dumpDo;
...
}
#Data
#Builder
#Entity
#Table(name = "thread_dump")
#AllArgsConstructor
#NoArgsConstructor
public class ThreadDumpDo implements Serializable {
private static final long serialVersionUID = -1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(
mappedBy = "dumpDo",
cascade = CascadeType.ALL,
orphanRemoval = true
)
private List<ThreadDo> threadDoList;
}
And then I have a ThreadDoRepository and want to locate the threadDos directly like this:
List<ThreadDo> findAllByDumpDoAndLocksWaitingContains(Long dumpId, String lockWaiting);
I can achieve it via #Query as follows, but I really think it's pretty ugly since it's easy to interpret (I think).
#Query(value = "select * from thread_info t where t.thread_dump_id = ?1 and t.locks_waiting like ?2",
nativeQuery = true)
List<ThreadDo> findAllByDumpDoAndLocksWaitingContains(Long dumpId, String lockWaiting);
Try this
List<ThreadDo> findAllByDumpDo_IdAndLocksWaitingContains(Long dumpId, String lockWaiting);
I have many to many relation between User and Event. I need to have extra column in relational table. I did id:
#Entity
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#OneToMany(mappedBy="user")
private Set<EventUser> eventUsers = new HashSet<>();
//
}
#Entity
public class Event {
#Id
#GeneratedValue(strategy= GenerationType.AUTO)
private long id;
#OneToMany(mappedBy="event")
private Set<EventUser> eventUsers = new HashSet<>();
//
}
#Entity
#Table(name = "Event_User")
public class EventUser {
#Id
#GeneratedValue(strategy= GenerationType.AUTO)
private long id;
private String reaction;
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "user_id")
private User user;
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "event_id")
private Event event;
//
}
But now... I don't know how to load all events where user has concrete email. Before it I used method:
findByUsersEmail(String email);
Now I can't do this, because Event doesn't have Set users field.
Any ideas ?
What you need here is property-expressions.
Just a quick idea to start:
findByEventUsers_UserEmail(String email);
Note: Dont forget that creating queries by method names is a very limited approach and only used by trivial cases. In any other case, don't be afraid of using the #Query annotation on the method or write JPQL/Criteria API manually.
I have an unidirectional OneToMany JPA entity mapping in my (Spring Framework + Spring Data + Hibernate JPA) project. Entity classes are like in the following code.(I have removed irrelevant class members for brevity).
#Entity
#Table(name = "employees")
class Employee{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private Integer id;
#OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
#JoinColumn(name = "employee_id")
private List<DepartmentAssignment> departmentAssignments = new ArrayList<>();
}
#Entity
#Table(name = "department_assignments")
class DepartmentAssignment{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private Integer id;
#NotNull
#Column(name = "employee_id")
private Integer employeeId;
#NotNull
#Column(name = "department_id")
private Integer departmentId;
}
#Entity
#Table(name = "departments")
class Department{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private Integer id;
}
And, in one of my service classes have a method to remove a DepartmentAssignment from an Employee like below.
public Employee deleteDepartmentAssignment(Integer empId, Integer deptAssignmentId) {
Employee employee = employeeRepository.findOne(empId);
if(employee != null) {
for ( DepartmentAssignment da : employee.getDepartmentAssignments()) {
if(da.getId().equals(deptAssignmentId)) {
employee.getDepartmentAssignments().remove(da);
employee = employeeRepository.save(employee);
break;
}
}
}
return employee;
}
However, calling above methods gives me an error: org.hibernate.exception.ConstraintViolationException ,and in the SQL log, I can see Column 'employee_id' cannot be null error for the last SQL statement of the transaction.
Can anybody tell me what I'm doing wrong here and how to get it fixed?
You don't need to add
#NotNull
#Column(name = "employee_id")
private Integer employeeId;
to the Employee, if you use #JoinColumn(name = "employee_id"). Try to remove it.
You can try the following, not sure why you use the plain id in the object. Thats not object relational mapping.
For more details see Hibernate triggering constraint violations using orphanRemoval
#Entity
#Table(name = "employees")
class Employee{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "employee", orphanRemoval = true)
private List<DepartmentAssignment> departmentAssignments = new ArrayList<>();
}
#Entity
#Table(name = "department_assignments")
class DepartmentAssignment{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#ManyToOne(optional=false)
private Employee employee;
#ManyToOne(optional=false)
private Department department;
}
#Entity
#Table(name = "departments")
class Department{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
}
You must look .hbm.xml file and you should mapping your Entity in this file and
you can look this example
http://www.mkyong.com/hibernate/hibernate-one-to-many-relationship-example/
I hope it will be useful for you.
try removing
cascade = CascadeType.ALL
but im not 100% sure..