Updating table is not happening through Setters in Spring JPA - spring

Question

I am new to Spring boot and Spring Data JPA . So here i am trying to implement a sample project where a employee has list of workers , while adding a new worker has employee details also to indicate that he works for particular employee. I am able to update the worker table and also fetch the details perfectly . Am trying to update Employee table as well so that while fetching a particular employee i want the list of workers associated with him also to be fetched . But that is not happening , i haven't used any query so far as it seems simple updation and i thought just save and setters would help to do so .
Employee.Java
#Entity
public class Employee {
#Id
private int empId;
private String empName;
private String location;
#OneToMany
private List<Worker> workers;
public Employee(){
}
public Employee(int empId, String empName, String location) {
super();
this.empId = empId;
this.empName = empName;
this.location = location;
}
public List<Worker> getWorkers() {
return workers;
}
public void setWorkers(List<Worker> workers) {
this.workers = workers;
}
public int getEmpId() {
return empId;
}
public void setEmpId(int empId) {
this.empId = empId;
}
public String getEmpName() {
return empName;
}
public void setEmpName(String empName) {
this.empName = empName;
}
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public void setWorkers(Worker worker) {
this.workers.add(worker);
}
#Override
public String toString() {
return "Employee [empId=" + empId + ", empName=" + empName + ", location=" + location + ", workers=" + workers
+ "]";
}
/*#Override
public String toString() {
return "Employee [empId=" + empId + ", empName=" + empName + ", location=" + location + "]";
}*/
Worker.Java
#Entity
public class Worker {
#Id
private int id;
private String name;
#ManyToOne
#JoinColumn(name="empId")
private Employee employee;
public Worker(int id, String name , int empId) {
super();
this.id = id;
this.name = name;
this.employee = new Employee(empId,"","");
}
public Worker() {
// TODO Auto-generated constructor stub
}
public Employee getEmployee() {
return employee;
}
public void setEmployee(Employee employee) {
this.employee = employee;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
WorkerController.Java
#RestController
public class WorkerController {
#Autowired
WorkerRepository workerService;
#Autowired
EmployeeRepository employeeService;
#GetMapping("/employees/{id}/workers")
public List<Worker> getAllWorker(#PathVariable("id") int empId){
return workerService.findByEmployeeEmpId(empId);
}
#PostMapping("/employees/{id}/workers")
public String addNewEmployee(#RequestParam("name") String name ,
#RequestParam("workerId") int id , #PathVariable("id") int empId){
Worker worker = new Worker();
List<Worker> workers = new ArrayList<Worker>();
worker.setId(id);
worker.setName(name);
worker.setEmployee(new Employee(empId,"",""));
workerService.save(worker);
workers.add(worker);
employeeService.findById(empId).get().setWorkers(workers);
Employee emp = new Employee();
emp = employeeService.findById(empId).get();
return "Successfully added";
}
}
After adding worker , i retrieve the following as output
[
{
"id": 108,
"name": "vijay",
"employee": {
"empId": 99,
"empName": "darsha",
"location": "mumbai",
"workers": []
}
},
{
"id": 110,
"name": "suraj",
"employee": {
"empId": 99,
"empName": "darsha",
"location": "mumbai",
"workers": []
}
}
]
but while retrieving i could see the employee table is not updated. can someone guide me .
{
"empId": 99,
"empName": "darsha",
"location": "mumbai",
"workers": []
}

Answer 1

You says:
"...while fetching a particular employee i want the list of workers
associated with him also to be fetched"
then you have to write a OneToMany Relationship on employee's side. What you do is you tries to fetch for each Worker one Employee which is of course working and is there in your JSON result.
Here is a OneToMany Example on Emplyees class side:
#OneToMany(mappedBy="employee", fetch=FetchType.EAGER, cascade=CascadeType.ALL)
private List<Worker> worker = new ArrayList<>();
Note: mappedBy have to refer to the variable Emplyee employee in your Worker Class.
Please try different fetch types also.

Answer 2

Why you are not getting your #OneToMany attributes is due fetch type is lazy by default for all #OneToMany associations like list, set.
To overcome this problem. Change the default lazy fetch to eager fetch.
Modify your entity mapping to this.
#OneToMany(mappedBy="employee", fetch=FetchType.EAGER, cascade=CascadeType.ALL) private List<Worker> worker = new ArrayList<>();
while fetching you may get recursive mapping. To avoid this just add #JsonIgnoreProperties to your employee field in worker class.
Example:
#JsonIgnoreProperties("employee")
#ManyToOne
#JoinColumn(name="empId")
private Employee employee;