m5kuVp9U

1@Entity
2@Table(name = "users")
3public class User implements Serializable {
4
5    @Id
6    @GeneratedValue(strategy = GenerationType.IDENTITY)
7    private int id;
8
9    @Column(name = "`name`", nullable = false, unique = true)
10    private String name;
11
12    @OneToMany(fetch = FetchType.EAGER, mappedBy = "author")
13    private Set<Document> authorDocuments = new HashSet<>();
14
15    @OneToMany(fetch = FetchType.EAGER, mappedBy = "concurrent")
16    private Set<Document> concurrentDocuments = new HashSet<>();
17
18    public User() {
19    }
20
21    public User(String name) {
22        this.name = name;
23    }
24
25    public int getId() {
26        return id;
27    }
28
29    public void setId(int id) {
30        this.id = id;
31    }
32
33    public String getName() {
34        return name;
35    }
36
37    public void setName(String name) {
38        this.name = name;
39    }
40
41    public Set<Document> getAuthorDocuments() {
42        return authorDocuments;
43    }
44
45    public Set<Document> getConcurrentDocuments() {
46        return concurrentDocuments;
47    }
48
49    public void addDocumentAuthor(Document document) {
50        authorDocuments.add(document);
51        document.setAuthor(this);
52    }
53
54    public void removeDocumentAuthor(Document document) {
55        authorDocuments.remove(document);
56        document.setAuthor(null);
57    }
58
59    public void addDocumentConcurrent(Document document) {
60        concurrentDocuments.add(document);
61        document.setConcurrent(this);
62    }
63
64    public void removeDocumentConcurrent(Document document) {
65        concurrentDocuments.remove(document);
66        document.setConcurrent(null);
67    }
68
69}
70	
71@Entity
72@Table(name = "documents")
73public class Document implements Serializable {
74
75    @Id
76    @GeneratedValue(strategy = GenerationType.IDENTITY)
77    private int id;
78
79    @Column(name = "`name`", nullable = false, unique = true)
80    private String name;
81
82    @ManyToOne(fetch = FetchType.EAGER)
83    @JoinColumn(name = "id_author", nullable = false)
84    private User author;
85
86    @ManyToOne(fetch = FetchType.EAGER)
87    @JoinColumn(name = "id_concurrent", nullable = false)
88    private User concurrent;
89
90    public Document() {
91    }
92
93    public Document(String name) {
94        this.name = name;
95    }
96
97    public int getId() {
98        return id;
99    }
100
101    public void setId(int id) {
102        this.id = id;
103    }
104
105    public String getName() {
106        return name;
107    }
108
109    public void setName(String name) {
110        this.name = name;
111    }
112
113    public User getAuthor() {
114        return author;
115    }
116
117    public void setAuthor(User author) {
118        this.author = author;
119    }
120
121    public User getConcurrent() {
122        return concurrent;
123    }
124
125    public void setConcurrent(User concurrent) {
126        this.concurrent = concurrent;
127    }
128
129    @Override
130    public String toString() {
131        return "Document {" + lineSeparator()
132                + "name: " + name + "," + lineSeparator()
133                + "author: " + author.getName() + "," + lineSeparator()
134                + "concurrent: " + concurrent.getName() + lineSeparator()
135                + "}";
136    }
137
138}
139	
140@Repository
141public interface DocumentRepository extends CrudRepository<Document, Integer> {
142
143}
144	
145@Repository
146public interface UserRepository extends CrudRepository<User, Integer> {
147
148}
149	
150spring.jpa.hibernate.ddl-auto=validate
151spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
152spring.jpa.show-sql=true
153
154spring.datasource.url=jdbc:mysql://localhost:3306/many_to_many?useSSL=false
155spring.datasource.username=root
156spring.datasource.password=root
157spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
158	
159drop database if exists many_to_many;
160create database many_to_many;
161use many_to_many;
162
163create table users (
164    id int primary key auto_increment,
165    `name` varchar(255) not null unique
166);
167
168create table documents (
169    id int primary key auto_increment,
170    `name` varchar(255) not null unique,
171    id_author int not null,
172    id_concurrent int not null,
173    foreign key(id_author) references users(id),
174    foreign key(id_concurrent) references users(id)
175);
176	
177@SpringBootApplication
178public class Application implements CommandLineRunner {
179
180    @Autowired
181    private UserRepository userRepository;
182
183    @Autowired
184    private DocumentRepository documentRepository;
185
186    public static void main(String[] args) {
187        SpringApplication.run(Application.class, args);
188    }
189
190    @Override
191    public void run(String... args) throws Exception {
192        User user1 = new User("user1");
193        User user2 = new User("user2");
194        User user3 = new User("user3");
195
196        userRepository.save(user1);
197        userRepository.save(user2);
198        userRepository.save(user3);
199
200        Document document1 = new Document("document1");
201        Document document2 = new Document("document2");
202
203        user1.addDocumentAuthor(document1);
204        user2.addDocumentConcurrent(document1);
205
206        user1.addDocumentAuthor(document2);
207        user3.addDocumentConcurrent(document2);
208
209        documentRepository.save(document1);
210        documentRepository.save(document2);
211
212        documentRepository.findAll().forEach(System.out::println);
213    }
214
215}
216	
217Document {
218name: document1,
219author: user1,
220concurrent: user2,
221}
222Document {
223name: document2,
224author: user1,
225concurrent: user3,
226}