I am doing a spring boot tutorial for fun. I understand that each entity can be defined by a model with a repository that the controller for that entity uses to create endpoints. I am wondering what is the best practice to create an endpoint in a controller that involves more than one model. I.e. we have a session model and speaker model below and i want to have a endpoint that returns all sessions with a speaker of a certain last name (many to many). Do I have to use both repositories? Is it even good practice to put this in session's controller since it also involves speaker? See the example below. Sorry if the question is stupid, I am trying to learn Spring-Boot and I am completely new to it.
//Session class
#Entity(name="sessions")
#JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class Session {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long session_id;
private String session_name;
private String session_description;
private Integer session_length;
#ManyToMany
#JoinTable(
name = "session_speakers",
joinColumns = #JoinColumn(name="session_id"),
inverseJoinColumns = #JoinColumn(name= "speaker_id"))
private List<Speaker> speakers;
}
//Speaker
#Entity(name="speakers")
#JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class Speaker {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long speaker_id;
private String first_name;
private String last_name;
private String title;
private String company;
private String speaker_bio;
#ManyToMany(mappedBy = "speakers")
#JsonIgnore
private List<Session> sessions;
#RestController
#RequestMapping("/api/v1/sessions")
public class SessionsController {
#Autowired
private SessionRepository sessionRepository;
#GetMapping
#RequestMapping("{id}")
public Session getSessionsBySpeakerName(#PathVariable String lname{
//want to implement
}
Controllers are supposed to be very light,so it would be better to have seperate controllers.
Usualy it is good to have seperate Repositories also so that later on if you want to add a new table you would not be touching the existing stable code, it sould be loosly coupled as much as possible
Here are few blog posts which I found useful.
https://www.e4developer.com/2018/08/06/spring-boot-best-practices/
https://dzone.com/articles/spring-boot-best-practices-for-microservices
https://www.javaguides.net/2019/03/spring-boot-best-practices.html
Related
I have a spring boot JPA project with an entity called Customers and another one CustomerReports
#Entity
public class Customers {
#Id
#GeneratedValue(strategy= GenerationType.IDENTITY)
private int id;
private String Name;
#JsonIgnore
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "customer_id", referencedColumnName = "id")
private Reports reports;
//getter and setters..etc
}
#Entity
public class CustomerReports {
#Id
#GeneratedValue(strategy= GenerationType.IDENTITY)
private int id;
private BigDecimal monthlyPayment;
//done
#JsonIgnore
#OneToOne(mappedBy = "reports")
private Customers customers;
//constructors, getters...etc.
}
I want whenever I insert a Customer, a report to also be generated for that customer. The column "monthlyPayment" in reports is also generated through a reference from another table so I don't want to insert those columns manually if that makes sense.
Is there a way to do that? I'm not sure what to google so it would be great if anyone can give me an idea
If I understand your question properly, you can derive CustomerReports entity based on Customers via simple java utility method & then call save if you are using jparepository :
CustomerReports customerReports=reportUtil(customerEntity);
jpaRepository.save(customerEntity);
jpaRepository.save(customerReports);
...
private CustomerReports reportUtil(Customers customerEntity){
/*Derive values for CustomerReports based on Customers & return*/
}
Or if you don't want to do by this way then check if your underlying database support triggers which you can use for inserting data into CustomerReports while doing insert to Customers
I know there has been multiple questions on bidirectional relations using spring jpa in the past but my case is a little bit different because i am using 3 entities with 2 relationships to implement a medical system
I have 3 entities : doctor/patient/appointment
here is the code for the 3 entities
please note all setters , getters and constructors implemented but ommited here for clarity
Patient class
#Entity
public class resPatient {
#Id
#GeneratedValue( strategy= GenerationType.IDENTITY )
private long code;
private String name;
private String gender;
private String email;
private String mobile;
private int age;
private String notes;
#OneToMany(mappedBy = "patient")
List<resPackageMembership> memberships;
#OneToMany(mappedBy = "patient")
List<resAppointment> appointments;
#OneToMany(fetch = FetchType.LAZY,mappedBy = "patient")
List<resMedImage> medImages;
Doctor class
#Entity
public class resDoctor {
#Id
#GeneratedValue( strategy= GenerationType.IDENTITY )
private long code;
private String name;
private String mobile;
private String email;
private String gender;
private int age;
private String speciality;
#OneToMany(mappedBy = "doctor")
List<resAppointment> appointments;
Appointment class
#Entity
public class resAppointment {
#Id
#GeneratedValue( strategy= GenerationType.IDENTITY )
private long code;
private String speciality;
#Basic
#Temporal(TemporalType.TIMESTAMP)
private Date dateCreated;
#Basic
#Temporal(TemporalType.TIMESTAMP)
private Date dateToVisit;
private String status;
private String notes;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "doctorCode")
private resDoctor doctor;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "patientCode")
private resPatient patient;
the way my medical system should work is that when i get a patient using my restful controller i want all the patient data including his appointments but this leads to an infinite loop as the appointment has the doctor which also has appointments and so on.
i cannot user #JSONIGNORE as there are 2 relationships i want to get the patient with his appointments which should have the doctor without the appointments array and should not have any patient data as i already am in the patient object
As a general best-practice, it's recommended to separate the entities from the data transfer objects used for the rest controllers. With DTO's in place, you have more control on which data to include and serialize within them to avoid the circlular references.
If you like check out https://bootify.io, it generates the DTOs from your database schema, but the custom endpoint you still need to define/build.
I develop an annotation processor called beanknife recently, it support generate DTO from any class. You need config by annotation. But you don't need change the original class. This library support configuring on a separate class. Of course you can choose which property you want and which you not need. And you can add new property by the static method in the config class. For your question:
// this will generate a DTO class named "resPatientView".
// You can change this name using genName attribute.
#ViewOf(value=resPatient.class, includePattern = ".*")
public class PatientViewConfigure {
// here tell the processor to automatically convert the property appointments from List<resAppointment> to List<resAppointmentWithoutPatient>.
// resAppointmentWithoutPatient is the generated class configured at the following.
// Note, although at this moment it not exists and your idea think it is an error.
// this code really can be compiled, and after compiled, all will ok.
#OverrideViewProperty("appointments")
private List<resAppointmentWithoutPatient> appointments;
}
// here generated a class named resAppointmentWithoutPatient whick has all properties of resAppointment except patient
#ViewOf(value=resAppointment.class, genName="resAppointmentWithoutPatient", includePattern = ".*", excludes={"patient"})
public class AppointmentWithoutPatientViewConfigure {
// the doctor property will be converted to its dto version which defined by the configure class DoctorWithoutAppointmentsViewConfigure.
#OverrideViewProperty("doctor")
private resDoctorWithoutAppointments doctor;
}
// here we generate a class which has all properties of resDoctor except appointments
#ViewOf(value=resDoctor.class, genName="resDoctorWithoutAppointments", includePattern = ".*", excludes={"appointments"})
public class DoctorWithoutAppointmentsViewConfigure {}
// in you rest controller. return the dto instead of the entities.
resPatient patient = ...
resPatientView dto = resPatientView.read(patient);
List<resPatient> patients = ...
List<resPatientView> dto = resPatientView.read(patients);
At the end, the class resPatientView will has the same shap with resPatient except its appointments not having patient property and its doctor property is replaced with a version without appointments property.
Here are more examples.
The version 1.10 is ready. Will fix some bug and support the configure bean to be managed by spring.
I am using spring boot (version - 2.1.1). I have a one to many database model exposed for CRUD operations through rest api's. The model looks as below. How do I configure the POST /departments api (that creates a department object) to accept just the organization id in the input json body?
#PostMapping
public Long createDepartment(#RequestBody Department Department) {
Department d = departmentService.save(Department);
return d.getId();
}
Note - I do not want to allow creating organization object when creating a department.
Model object mapping
#Entity
#Table(name="ORGANIZATIONS")
public class Organization{
#Id
#GeneratedValue
Private long id;
#Column(unique=true)
Private String name;
#OneToMany(mappedBy = "organization", fetch = FetchType.EAGER)
private List<Department> departments;
}
#Entity
#Table(name="DEPARTMENTS")
Public class Department{
#Id
#GeneratedValue
Private long id;
#Column(unique=true)
Private String name;
#ManyToOne(fetch = FetchType.EAGER)
private Organization organization;
}
Thanks!
The easiest and most sane way in my opinion is to utilize the DTO (Data Transfer Object) pattern.
Create a class that represent the model you want to get as your input:
public class CreateDepartmentRequest {
private long id;
// getters and setters
}
Then use it in your controller:
#PostMapping
public Long createDepartment(#RequestBody CreateDepartmentRequest request) {
Department d = new Department();
d.setId(request.getId());
Department d = departmentService.save(d);
return d.getId();
}
Side note, its better to ALWAYS return JSON through REST API (unless you use some other format across your APIs) so you can also utilize the same pattern as I mentioned above to return a proper model as a result of the POST operation or a simple Map if you don't want to create to many models.
I have two pojo classes with one-to-many relationship in hibernate
CustomerAccountEnduserOrderDetails.class
#Entity #Table(name="customer_account_enduser_order_details")
public class CustomerAccountEnduserOrderDetails implements Serializable{
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
#Column(name="id")
private Long id;
#ManyToOne(fetch=FetchType.EAGER)
#JoinColumn(name = "product_id", insertable = false, updatable = false)
private CustomerCmsProduct customerCmsProduct;
}
Second is CustomerCmsProduct.class
#Entity
#Table(name="customer_cms_product")
#JsonIgnoreProperties(ignoreUnknown = true)
public class CustomerCmsProduct {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name="id")
private Long id;
#Column(name="name")
private String name;
#Column(name="offer_price")
private String offerPrice;
#Column(name="original_price")
private String originalPrice;
#Column(name="discount")
private String discount;
}
Here if I fetch the object of CustomerAccountEnduserOrderDetails class,then i will get the CustomerCmsProduct class also , my problem is that here i want the specific column of CustomerCmsProduct table (not all by default i am getting all) like only id and originalPrice.
How i can do like that projection here?
In the service layer or at a webservice layer( if this is a web project) Create two different classes other than #Entity as DTO(Data Transfer Objects) which helps is data transfer from one layer to the other.
public class CustomerAccountEnduserOrderDetailsPojo {
private List<CustomerCmsProductPojo> productPojoList = new ArrayList<> ();
// getter and setter
}
public class CustomerCmsProductPojo {}
Follow the below steps
Retrieve the #Entity class data by executing the query from service layer.
Iterate over all the fields and copy only required fields to pojo layer
Expose the data to other layers using service method.
This way, we can avoid changing the custom hibernate behavior as it is linked with many parameters like cache, one to many queries that are fired per iteration.
And also, do any customization that you want in this layer. Hope this is multi layered project where you have different layers which servers different purpose.
Hi I am new to Spring Data JPA and I am wondering even though I pass the Id to the entity, the Spring data jpa is inserting instead of merge. I thought when I implement the Persistable interface and implement the two methods:
public Long getId();
public Boolean isNew();
It will automatically merge instead of persist.
I have an entity class called User like:
#Entity
#Table(name = "T_USER")
public class User implements Serializable, Persistable<Long> {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "USER_ID")
private Long id;
#Column(name = "CREATION_TIME", nullable = false)
private Date creationTime;
#Column(name = "FIRST_NAME", nullable = false)
private String firstName;
#Column(name = "LAST_NAME", nullable = false)
private String lastName;
#Column(name = "MODIFICATION_TIME", nullable = false)
private Date modificationTime;
And have another class
#Entity
#Table(name = "T_USER_ROLE")
public class UserRole implements Serializable, Persistable<Long> {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long roleId;
#Column(name = "ROLE_NAME")
private String userRole;
}
I have a custom repository called UserRepostory extending JpaReopistory. I am hitting the save for merge and persist as I see the implementation demonstrate that Spring Data Jpa uses above two methods to either update or insert.
#Repository
public interface UserRepository extends JpaRepository<User, Long> {
}
I have been trying to figure out but didn't get any clue. Maybe you
guys can help.
I ran into this issue, tried to implement Persistable to no avail, and then looked into the Spring Data JPA source. I don't necessarily see this in your example code, but I have a #Version field in my entity. If there is a #Version field Spring Data will test that value to determine if the entity is new or not. If the #Version field is not a primitive and is null then the entity is considered new.
This threw me for a long time in my tests because I was not setting the version field in my representation but only on the persisted entity. I also don't see this documented in the otherwise helpful Spring Data docs (which is another issue...).
Hope that helps someone!
By default Spring Data JPA inspects the identifier property of the given entity. If the identifier property is null, then the entity will be assumed as new, otherwise as not new. It's Id-Property inspection Reference
If you are using Spring JPA with EntityManager calling .merge() will update your entity and .persist() will insert.
#PersistenceContext
private EntityManager em;
#Override
#Transactional
public User save(User user) {
if (user.getId() == null) {
em.persist(user);
return user;
} else {
return em.merge(user);
}
}
There is no need to implement the Persistable interface.