I am relatively new to Spring. I'm trying to implement a simple CRUD RESTful API for MongoDB. I'm having issues with mapping annotations when it comes to polymorphic classes.
Here's my Employee class that holds a list of Allocations. The idea is that an employee can have multiple allocations at once. An Allocation could either be a training or a department.
public class Employee {
#Id
private String id;
private String empCode;
private String firstName;
private String lastName;
private List<Allocation> allocations;
// Getters, setters and Constructor
}
Here's the Allocation class.
public class Allocation {
#Id
private String id;
private LocalDate startDate;
private LocalDate endDate;
private String location;
}
And here are the Department and Training classes.
public class Training extends Allocation {
#Id
private String id;
private String courseName;
}
public class Department extends Allocation {
#Id
private String id;
private String deptName;
}
How do I map the above classes using Spring annotations? When I retrieve an Employee, I want the JSON to have an array of Allocations that include both Training Programs and Departments.
Related
Here's nodeEntity
#Data
#NodeEntity
public class Resource {
#Id
#GeneratedValue
private Long id;
#Property("name")
private String name;
private String code;
#Property("parent_code")
private String parentCode;
private String label;
private Neo4jRelationship relationship;
}
And here's relationship between nodes
#Data
#RelationshipEntity
public class Neo4jRelationship {
#Id
private Long id;
#StartNode
private Resource startNode;
#EndNode
private Resource endNode;
}
I want to query all the relationship satify some condition,
#Query("match p = (a : category_first {name: $name})-[*1..2]-() return p")
List<Neo4jRelationship> getFistCatNode(#Param("name") String name);
but the query return am empty list.
However, if I change the return type to org.neo4j.ogm.model.Result, the query can return normally.
I'm confused why the first way dosen't work. Any help will be grateful
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.
So i have two entity classes Employee and Address and they are in #OneToOne Relation I'm able to search a Employee's with different parameter like name,designation,department. But i want to search a employee using address fields like Areaname,pincode, phone etc.. How to implement this functionality i'm currently using JpaRepo with Mysql.
#Entity
public class Employee{
#Id#GeneratedValue(strategy=GenerationType.AUTO)
private int id;
private String Name;
private String Designation;
private String Department;
#OneToOne(cascade=CascadeType.ALL)
private Address address;}
#Entity
public class Address{
private String Streetname;
private String Areaname;
private String City;
private Long pincode;
#Id
private Long phone;
}
try like this:
#Query("FROM Employee AS emp LEFT JOIN emp.address AS adr WHERE adr.areaname= ?1")
public List<Employee > FindAllEmployeeByAreaName(String areaname);
I am currently learning spring boot , hibernate and Spring Boot JPA
I developing a Classroom App for coaching centers and institutes .
In it, students enrolled to multiple courses in a single institute
The Student Entity class :
#Entity
#Table(name = "student")
public class Student {
private String name;
private String dob;
private String gender;
private String address;
private String email;
private Integer mobile;
private String joined;
private Integer instID;
#Id
private String studentid;
getters and setters()....
}
Course Table Entity class
#Entity
#Table(name = "courses")
public class Course {
private String name;
private String description;
private String logo;
private String start;
private String end;
private Integer fee;
#Id
private String courseid;
private Integer instID;
getters and setters();
}
Enrolled Classes Table's Entity class
public class EnrolledCourses {
#Id
String enrollID;
String courseid;
String studentid;
Date joined;
getters and setters()...
}
JPA Repository
#Repository
public interface StudentRepository extends CrudRepository<Student, String> {
Student findTopByInstIDOrderByStudentidDesc(int instID);
}
#Repository
public interface CourseRepository extends CrudRepository<Course,String> {
}
#Repository
public interface EnrolledRepository extends CrudRepository<Course,String> {
}
My Need
Now I am retrieving enrolled students for a given course in a given institute... by using this MySQL query
SELECT
`enrolled_courses.enrollID`,
`student.name`, `student.studentid`
FROM `enrolled_courses`
INNER JOIN `student`
WHERE
`enrolled_courses.studentid` = `student.studentid`
AND
`student.instID` = 13
AND
`enrolled_courses.courseid` = '13I01C' ;
Now I need to implement this Inner join query in CourseRepository (or enrolledstudent repo)
How to achieve this ?
Please guide me
If we use hibernate mapping in EnrolledCourses entity like
#Entity
public class EnrolledCourses {
#Id
String enrolledId;
#ManyToOne
Student student;
#ManyToOne
Course course;
Date joined;
getters and setters()...
}
from the above mappings without using any SQL queries, you can retrieve all student who comes under a particular course
By using the method in the interface
#Repository
public interface EnrolledRepository extends CrudRepository<EnrolledCourses,String> {
List<EnrolledCourses> findByCourse_CourseId(String courseId);
}
if we have some relations between the entities we can easily retrieve all the fields using Jpa.
I am working on a spring boot application with Hibernate as ORM and Jackson as JSON serialiser .
I have three model objects and CRUD operations for all three models.
Class Student{
private Teacher teacher; // Teacher of the student — to be fetched eagerly
+Getter/Setter
}
class Teacher {
private List<Subject> subject; // List of subjects associated to that user— to be fetched eagerly
+Getter/Setter
}
class Subject {
private long subjectId
//Other subject properties
+ Getter/Setter
}
Whenever I trigger a get request for student info I get the teacher info which is correct where as I also receive Subject info as well which is unnecessary for me. In the same time when I request for Teacher info, I need Subject info should be associated to that for sure. If I use #JsonBackReference for subject I am losing it all the time. I am not sure how to achieve this.
Thanks in advance for your help!!
You can also annotate like this
Class Student{
#JsonIgnoreProperties("subject")
private Teacher teacher; // Teacher of the student — to be fetched eagerly
}
You can use JSON Views
From the spring blog:
public class View {
interface Summary {}
}
public class User {
#JsonView(View.Summary.class)
private Long id;
#JsonView(View.Summary.class)
private String firstname;
#JsonView(View.Summary.class)
private String lastname;
private String email;
private String address;
private String postalCode;
private String city;
private String country;
}
public class Message {
#JsonView(View.Summary.class)
private Long id;
#JsonView(View.Summary.class)
private LocalDate created;
#JsonView(View.Summary.class)
private String title;
#JsonView(View.Summary.class)
private User author;
private List<User> recipients;
private String body;
}
and in the controller
#RestController
public class MessageController {
#Autowired
private MessageService messageService;
#JsonView(View.Summary.class)
#RequestMapping("/")
public List<Message> getAllMessages() {
return messageService.getAll();
}
#RequestMapping("/{id}")
public Message getMessage(#PathVariable Long id) {
return messageService.get(id);
}
}
PS: No link to http://fasterxml.com/ as it's currently down.