Spring JPA OneToOne

Question

I'm skilling in the bunch of Spring boot with Thymeleaf and MySQL DB at localhost. I know how retrieve data from table via th:each tag, but how retrieve data from 2 tables? They linked one to one so I want to get results from both tables to one html page(f.e. for each instructor his own details), but i dunno how to release it or what to google. Anyone can help me or advice a book or article?

tables schema sql

set foreign_key_checks = 0;
DROP TABLE IF EXISTS instructor;
DROP TABLE IF EXISTS insturctor_detail;

CREATE TABLE IF NOT EXISTS instructor(
id INT(20) AUTO_INCREMENT PRIMARY KEY,
first_name VARCHAR(20) DEFAULT NULL,
second_name VARCHAR(20) DEFAULT NULL,
email VARCHAR(20) DEFAULT NULL,
instructor_detail_id INT(20),   
CONSTRAINT FK_INSTRUCTOR_DETAIL_ID
FOREIGN KEY (instructor_detail_id)
REFERENCES instructor (id)
ON DELETE NO ACTION
ON UPDATE NO ACTION
);

CREATE TABLE IF NOT EXISTS instructor_detail(
id INT(20) AUTO_INCREMENT PRIMARY KEY,
hobby VARCHAR(50) DEFAULT NULL,
youtube_channel VARCHAR(100) DEFAULT NULL
);
set foreign_key_checks = 1;

Controller:

@Controller
public class MyController {

    @Autowired
    InstructorRepository instructorRepository;

    @GetMapping("/index")
    public String mainController(){
        return "index";
    }

    @GetMapping("/add")
    public String addInstructorForm(Model model){
        model.addAttribute("instructor", new Instructor());
        model.addAttribute("detail", new InstructorDetail());
        return "addInstructor";
    }

    @PostMapping("/add")
    public String submitForm(@ModelAttribute Instructor instructor, @ModelAttribute InstructorDetail instructorDetail){
        instructor.setInstructorDetail(instructorDetail);
        instructorRepository.save(instructor);
        return "redirect:/instructorsList";
    }

    @GetMapping("/instructorsList")
    public String getList(Model model){
        model.addAttribute("instructors",instructorRepository.findAll());
        return "instructorsList";
    }

}

Entities: Instructor.class

    @Entity
    @Table(name = "instructor")
    public class Instructor {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;

    @Column(name = "first_name")
    private String firstName;

    @Column(name = "second_name")
    private String secondName;

    @Column(name = "email")
    private String email;

    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "instructor_detail_id")
    private InstructorDetail instructorDetail;

    public Instructor() {
    }

    public Instructor(String firstName, String secondName, String email) {
        this.firstName = firstName;
        this.secondName = secondName;
        this.email = email;
    }

    public Instructor(String firstName, String secondName, String email, InstructorDetail instructorDetail) {
        this.firstName = firstName;
        this.secondName = secondName;
        this.email = email;
        this.instructorDetail = instructorDetail;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getSecondName() {
        return secondName;
    }

    public void setSecondName(String secondName) {
        this.secondName = secondName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public InstructorDetail getInstructorDetail() {
        return instructorDetail;
    }

    public void setInstructorDetail(InstructorDetail instructorDetail) {
        this.instructorDetail = instructorDetail;
    }
}

Instructor detail class

@Entity
@Table(name = "instructor_detail")
public class InstructorDetail {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;
    @Column(name = "hobby")
    private String hobby;
    @Column(name = "youtube_channel")
    private String youtubeChannel;


    public InstructorDetail() {
    }

    public InstructorDetail(String hobby, String youtubeChannel) {
        this.hobby = hobby;
        this.youtubeChannel = youtubeChannel;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getHobby() {
        return hobby;
    }

    public void setHobby(String hobby) {
        this.hobby = hobby;
    }

    public String getYoutubeChannel() {
        return youtubeChannel;
    }

    public void setYoutubeChannel(String youtubeChannel) {
        this.youtubeChannel = youtubeChannel;
    }
}

html list of instructors

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8"/>
    <title>Title</title>
</head>
<body>
<div class="container">
    <table>
        <thead>
        <th>First name</th>
        <th>Last name</th>
        <th>Email</th>

        </thead>
        <tbody>
        <tr data-th-each="instructor : ${instructors}">
            <td data-th-text="${instructor.firstName}"></td>
            <td data-th-text="${instructor.secondName}"></td>
            <td data-th-text="${instructor.email}"></td>
        </tr>
        </tbody>
    </table>
</div>
</body>
</html>

add instructor form

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8"/>
    <title>Title</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css" integrity="sha384-PsH8R72JQ3SOdhVi3uxftmaW6Vc51MKb0q5P2rRUpPvrszuE4W1povHYgTpBfshb" crossorigin="anonymous"/>
</head>
<body>
<div class="container">
    <h1>form</h1>
    <form action="#" data-th-action="@{/add}" data-th-object="${instructor}" method="post">
        <div class="form-group">
            <label for="1">name</label>
            <input class="form-control" id="1" type="text" data-th-field="${instructor.firstName}" placeholder="first name"/>
        </div>
        <div class="form-group">
            <label for="2">second name</label>
            <input class="form-control" id="2" type="text" data-th-field="${instructor.secondName}" placeholder="second name"/>
        </div>
        <button class="btn btn-primary">add</button>
    </form>
</div>


</body>
</html>

UPDATE FIXED

I've just fix it using next way:

First: create buffer class for storing fields of 2 entities Next: Add this class to list and pass list via MVC to thymeleaf template

@GetMapping("/instructorsList")
        public String getList(Model model){
            Map map = new HashMap<>();
            List list = new ArrayList<Instructor>();
            list = instructorRepository.findAll();
            List resultList = new ArrayList();
            for (int i = 0; i < list.size(); i++) {
                Instructor instructor = (Instructor)list.get(i);
                InstructorDetail detail = detailRepository.getInstructorDetailById(instructor.getId());
                InstructorAndDetail iid = new InstructorAndDetail(instructor, detail);
                resultList.add(iid);
            }
            model.addAttribute("instructors", resultList);
            return "instructorsList";
        }

and the class:

public class InstructorAndDetail {

    private String fname;
    private String lname;
    private String email;
    private String hobby;
    private String channel;

    public InstructorAndDetail() {
    }

    public InstructorAndDetail(Instructor instructor, InstructorDetail detail) {
        fname = instructor.getFirstName();
        lname = instructor.getSecondName();
        email = instructor.getEmail();
        hobby = detail.getHobby();
        channel = detail.getYoutubeChannel();


    }

    public String getFname() {
        return fname;
    }

Please refer below link for your reference. https://stackoverflow.com/questions/19977130/joining-two-table-entities-in-spring-data-jpa — darshakat, Dec 05 '17 at 05:43

Spring JPA OneToOne

0 Answers0