Question

我试图映射我的数据库表，以便我可以在Books和Author表之间建立多对多的关系。

首先，它是一对多的关系设计，感谢@xenteros和@Amer Qarabsa，我开始将它重新设计成多对多的关系。

所以，这就是我的数据库架构的样子：

作者（型号）类：

Entity
@Table(name = "author")
public class Author {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "author_id")
    private int id;
    @Column(name = "name")
    private String name;
    @Column(name = "surname")
    private String surname;
    @Column(name = "date_of_birth")
    private Date dateOfBirth;

    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "book_author",
            joinColumns = @JoinColumn(name = "book_id"),
            inverseJoinColumns = @JoinColumn(name = "author_id"))
    private Set<Book> authorsBooks = new HashSet<Book>();

    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;
    }


    public String getSurname() {
        return surname;
    }

    public void setSurname(String surname) {
        this.surname = surname;
    }


    public Date getDateOfBirth() {
        return dateOfBirth;
    }

    public void setDateOfBirth(Date dateOfBirth) {
        this.dateOfBirth = dateOfBirth;
    }

    public Set<Book> getAuthorsBooks() {
        return authorsBooks;
    }

    public void setAuthorsBooks(Set<Book> authorsBooks) {
        this.authorsBooks = authorsBooks;
    }
}

预订（模特）课程：

@Entity
@Table(name = "book")
public class Book {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "book_id")
    private int bookId;
    @Column(name = "title")
    private String title;
    @Column(name = "title_original")
    private String titleOriginal;
    @Column(name = "premiere_date")
    private Date premiereDate;
    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "book_author", joinColumns = { @JoinColumn(name = "book_id") }, inverseJoinColumns = { @JoinColumn(name = "author_id") })
    private Set<Author> booksAuthors = new HashSet<Author>(0);


    public int getBookId() {
        return bookId;
    }
    public void setBookId(int bookId) {
        this.bookId = bookId;
    }


    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }

    public String getTitleOriginal() {
        return titleOriginal;
    }
    public void setTitleOriginal(String titleOriginal) {
        this.titleOriginal = titleOriginal;
    }


    public Date getPremiereDate() {
        return premiereDate;
    }
    public void setPremiereDate(Date premiereDate) {
        this.premiereDate = premiereDate;
    }


    public Set<Author> getBookAuthors() {
        return this.booksAuthors;
    }
    public void setBookAuthors(Set<Author> bookAuthors) {
        this.booksAuthors = bookAuthors;
    }


}

AuthorController 类：

@Controller
public class AuthorController {

    @Autowired
    private AuthorRepository authorRepository;

    @RequestMapping(method = RequestMethod.GET)
    public ResponseEntity<Collection<Author>> getAuthors() {
        return new ResponseEntity<>(authorRepository.findAll(), HttpStatus.OK);
    }

    @RequestMapping(value = "/authors/{id}", method = RequestMethod.GET)
    public ResponseEntity<Author> getAuthor(@PathVariable int id) {
        Author author = authorRepository.findOne(id);

        if (author != null) {
            return new ResponseEntity<>(authorRepository.findOne(id), HttpStatus.OK);
        } else {
            return new ResponseEntity<>(HttpStatus.NOT_FOUND);
        }
    }

    @RequestMapping(method = RequestMethod.POST)
    public ResponseEntity<?> addAuthor(@RequestBody Author author) {
        return new ResponseEntity<>(authorRepository.save(author), HttpStatus.CREATED);
    }

    @RequestMapping(value = "/authors/{id}", method = RequestMethod.DELETE)
    public ResponseEntity<Void> deleteAuthor(@PathVariable int id) {
        authorRepository.delete(id);

        return new ResponseEntity<Void>(HttpStatus.OK);
    }

    /*
    @RequestMapping(value = {"/authors"}, method = RequestMethod.GET)
    public ModelAndView allAuthors() {
        ModelAndView modelAndView = new ModelAndView("authors/home"); //viewname przekazujemy z folderu templates
        List<Author> author = authorService.getAllAuthors();
        modelAndView.addObject("authors",author);  //ta nazwa tutaj "authors" sluzy potem do wykorzystania jej w templacie
        return modelAndView;
    }
    */

}

BookController 类：

@Controller
public class BookController {

    @Autowired
    private BookRepository bookRepository;

    @RequestMapping(method = RequestMethod.GET)
    public ResponseEntity<Collection<Book>> getBooks() {
        return new ResponseEntity<>(bookRepository.findAll(), HttpStatus.OK);
    }

    @RequestMapping(value = "/books/{id}", method = RequestMethod.GET)
    public ResponseEntity<Book> getBook(@PathVariable int id) {
        Book book = bookRepository.findOne(id);

        if (book != null) {
            return new ResponseEntity<>(bookRepository.findOne(id), HttpStatus.OK);
        } else {
            return new ResponseEntity<>( HttpStatus.NOT_FOUND);
        }
    }

    @RequestMapping(method = RequestMethod.POST)
    public ResponseEntity<?> addBook(@RequestBody Book book) {
        return new ResponseEntity<>(bookRepository.save(book), HttpStatus.CREATED);
    }

    @RequestMapping(value = "/books/{id}", method = RequestMethod.DELETE)
    public ResponseEntity<Void> deleteBook(@PathVariable int id) {
        bookRepository.delete(id);

        return new ResponseEntity<Void>(HttpStatus.OK);
    }

    /*
    @RequestMapping(value = {"/books"}, method = RequestMethod.GET)
    public ModelAndView allBooks() {
        ModelAndView modelAndView = new ModelAndView("books/home"); //viewname przekazujemy z folderu templates
        List<Book> book = bookService.getAllBooks();
        modelAndView.addObject("books",book);  //ta nazwa tutaj "books" sluzy potem do wykorzystania jej w templacie
        return modelAndView;
    }
    */


}

Stacktrace：

Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2017-08-07 13:02:18.638 ERROR 6812 --- [  restartedMain] o.s.boot.SpringApplication               : Application startup failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'requestMappingHandlerMapping' defined in class path resource [org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.class]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: Ambiguous mapping. Cannot map 'bookController' method 
public org.springframework.http.ResponseEntity<?> eu.fitk.controller.BookController.addBook(eu.fitk.model.Book)
to {[],methods=[POST]}: There is already 'authorController' bean method
public org.springframework.http.ResponseEntity<?> eu.fitk.controller.AuthorController.addAuthor(eu.fitk.model.Author) mapped.
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1628) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at eu.fitk.BookwebApplication.main(BookwebApplication.java:9) [classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_73]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_73]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_73]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_73]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-1.5.6.RELEASE.jar:1.5.6.RELEASE]
Caused by: java.lang.IllegalStateException: Ambiguous mapping. Cannot map 'bookController' method 
public org.springframework.http.ResponseEntity<?> eu.fitk.controller.BookController.addBook(eu.fitk.model.Book)
to {[],methods=[POST]}: There is already 'authorController' bean method
public org.springframework.http.ResponseEntity<?> eu.fitk.controller.AuthorController.addAuthor(eu.fitk.model.Author) mapped.
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping$MappingRegistry.assertUniqueMethodMapping(AbstractHandlerMethodMapping.java:576) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping$MappingRegistry.register(AbstractHandlerMethodMapping.java:540) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.registerHandlerMethod(AbstractHandlerMethodMapping.java:264) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.detectHandlerMethods(AbstractHandlerMethodMapping.java:250) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.initHandlerMethods(AbstractHandlerMethodMapping.java:214) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.afterPropertiesSet(AbstractHandlerMethodMapping.java:184) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping.afterPropertiesSet(RequestMappingHandlerMapping.java:127) ~[spring-webmvc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1687) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1624) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    ... 21 common frames omitted


Process finished with exit code 0

Answer 1

您必须拥有getId()方法或使用@Id注释的字段。将注释移动到字段，一切都会正常工作。

此外，您的关系不是@OneToMany。作者不能成为很多书的作者吗？它是@ManyToMany。

您的问题也在于，您有两个以相同方式调用的表。将联接表的名称更改为book-author或类似名称。

Answer 2

您的联接表的名称不应与您的某个表相同例如改为book_author

    @JoinTable(name = "book_author", joinColumns = { @JoinColumn(name = "book_id") }, inverseJoinColumns = { @JoinColumn(name = "author_id") })

Answer 3

问题在于：

@RequestMapping(method = RequestMethod.POST)
    public ResponseEntity<?> addBook(@RequestBody Book book) {
        return new ResponseEntity<>(bookRepository.save(book), HttpStatus.CREATED);
    }

@RequestMapping(value="/addauthor", method = RequestMethod.POST)
    public ResponseEntity<?> addAuthor(@RequestBody Author author) {
        return new ResponseEntity<>(authorRepository.save(author), HttpStatus.CREATED);
    }

方法具有相同的默认值＆＃34;值＆＃34;并且在进入＆＃34; /＆＃34;时，Hibernate无法确定从中选择哪一个。 ADRESS。解决方案只是添加不同的映射值：

@RequestMapping(value="/addauthor", method = RequestMethod.POST)
    public ResponseEntity<?> addAuthor(@RequestBody Author author) {
        return new ResponseEntity<>(authorRepository.save(author), HttpStatus.CREATED);
    }
@RequestMapping(value = "/addbook", method = RequestMethod.POST)
    public ResponseEntity<?> addBook(@RequestBody Book book) {
        return new ResponseEntity<>(bookRepository.save(book), HttpStatus.CREATED);
    }

Hibernate有很多很多关系

3 个答案: