引起：org.h2.jdbc.JdbcSQLException: 数据转换错误转换

Posted 2023-04-11

【中文标题】引起：org.h2.jdbc.JdbcSQLException: 数据转换错误转换

【英文标题】：Caused by: org.h2.jdbc.JdbcSQLException: Data conversion error converting

【发布时间】：2019-10-31 15:12:24

【问题描述】：

我使用了一个 Spring Boot 项目，该项目读取 CSV 文件并将数据保存在 H2 数据库中。

下面提供了 CSV 文件-

authors.csv

email;firstname;lastname 
[e-mail];Paul;Walter 
[e-mail];Max;Mülle

books.csv

title;isbn;bookAuthors;description 

Ich helfe dir kochen. Das erfolgreiche Universalkochbuch mit großem Backteil;5554-5545-4518;[e-mail],[e-mail];Auf der Suche nach einem Basiskochbuch steht man heutzutage vor einer Fülle von Alternativen. Es fällt schwer, daraus die für sich passende Mixtur aus Grundlagenwerk und Rezeptesammlung zu finden. Man sollte sich darüber im Klaren sein, welchen Schwerpunkt man setzen möchte oder von welchen Koch- und Backkenntnissen man bereits ausgehen kann.

杂志.csv

title;isbn;bookAuthors;publishedAt 

Beautiful cooking;5454-5587-3210;[e-mail];21.05.2011

我编写 POJO 文件，

@Entity
@Table(name = "Author")
public class Author implements Serializable 

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.TABLE)
    private Long id;


    // email;firstname;lastname

    @Column
    private String email;

    @Column
    private String firstname;

    @Column
    private String lastname;

    @ManyToMany(mappedBy = "bookAuthors", fetch = FetchType.LAZY)
    List<Book> books;

    @ManyToMany(mappedBy = "bookAuthors", fetch = FetchType.LAZY)
    List<Magazine> magazines;

    public Author() 

    

    public Author(String email, String firstname, String lastname) 
        this.email = email;
        this.firstname = firstname;
        this.lastname = lastname;
    




@Entity
@Table(name = "Book")
public class Book implements Serializable 

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;


    // title;isbn;bookAuthors;description
    @Column
    private String title;

    @Column
    private String isbn;

    @Column(length = 5000)
    private String description;

    @ElementCollection
    @Column(name="bookAuthors")
    List<String> bookAuthors;

    @ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(
            name = "book_authors",
            joinColumns = @JoinColumn(name = "book_id"),
            inverseJoinColumns = @JoinColumn(name = "author_id"))
    List<Author> authors;

    public Book() 

    

    public Book(String title, String isbn, String description) 
        this.title = title;
        this.isbn = isbn;
        this.description = description;
    




@Entity
@Table(name = "Magazine")
public class Magazine implements Serializable 

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;


    // title;isbn;bookAuthors;publishedAt
    @Column
    private String title;

    @Column
    private String isbn;

    @ElementCollection
    @Column(name = "bookAuthors")
    List<String> bookAuthors;

    @Column
    private String publishedAt;

    @ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(
            name = "magazine_authors",
            joinColumns = @JoinColumn(name = "magazine_id"),
            inverseJoinColumns = @JoinColumn(name = "author_id"))
    List<Author> authors;

    public Magazine() 

    

    public Magazine(String title, String isbn, String publishedAt) 

        this.title = title;
        this.isbn = isbn;
        this.publishedAt = publishedAt;
    

提供了存储库和服务文件的示例，

@Repository
public interface BookRepository extends JpaRepository<Book, Long> 


    @Query(value = "SELECT * FROM book WHERE book.isbn=:isbn",nativeQuery = true)
    Optional<Book> findBookByIsbn(String isbn);

服务文件，

@Service
public class BookService 


    private BookRepository repository;

    @Autowired
    public void setBookRepository(BookRepository BookRepository) 
        this.repository = BookRepository;
    

    @Transactional(rollbackFor = Exception.class)
    public Optional<Book> findById(Long id) 
        return repository.findById(id);
    

    @Transactional(rollbackFor = Exception.class)
    public List<Book> findAll() 
        return (List<Book>) repository.findAll();
    

    @Transactional(rollbackFor = Exception.class)
    public Book save(Book Product) 
        return repository.save(Product);
    

    @Transactional
    public <S extends Book> List<Book> saveAll(List<Book> students) 

        List<Book> result = new ArrayList<>();

        if (students == null) 
            return result;
        

        for (Book student : students) 
            result.add(repository.save(student));
        

        return result;
    

    @Transactional(rollbackFor = Exception.class)
    public void deleteAll() 
        repository.deleteAll();
    

    @Transactional(rollbackFor = Exception.class)
    public Optional<Book> findBookByIsbn(String isbn)
        return repository.findBookByIsbn(isbn);
    

当我尝试保存书籍数据时，我编写了代码，

String bookFilePath = "/Users/Chaklader/IdeaProjects/Publications/src/main/resources/data/books.csv";
        List<Book> books = new BookCsvFileReader(authorService).readBooksCsvData(bookFilePath);
        bookService.saveAll(books);

我得到了错误，

Caused by: org.h2.jdbc.JdbcSQLException: Data conversion error converting "'[e-mail]' (AUTHOR: ID BIGINT NOT NULL)"; SQL statement:
insert into book_book_authors (books_id, book_authors) values (?, ?) [22018-196]

如何纠正？

更新

BookCsvFileRead.java

public class BookCsvFileReader extends CsvFileReader 

    private AuthorService authorService;

    public BookCsvFileReader(AuthorService service) 
        this.authorService = service;
    

    public List<Book> readBooksCsvData(String fileName) throws IOException 

        List<Book> books = new ArrayList<>();

        try 
            List<List<String>> lines = CsvFileReader.readCsvFile(fileName);

            lines.remove(0);

            for (List<String> line : lines) 

                String title = line.get(0);
                String isbn = line.get(1);

                String[] emails = line.get(2).split(",");

                List<String> bookAuthors = new ArrayList<>();

                for (String email : emails) 
                    bookAuthors.add(email);
                

                String description = line.get(3);

                Book book = new Book(title, isbn, description, bookAuthors);
                book.setBookAuthors(bookAuthors);

                books.add(book);
            
        

        //
        catch (IOException e) 
            e.printStackTrace();
        

        return books;
    

【问题讨论】：

目前尚不清楚您是如何遇到这种情况的，但答案可能隐藏在您未添加到问题中的一段代码中。您能否也将BookCsvFileReader 的readBooksCsvData 方法添加到您的问题中？我相信根本问题是您的 CSV 文件使用电子邮件地址字符串作为作者 ID，但您将 Author 实体类建模为使用数字序列 ID。 CSV 阅读器中的某些内容可能会尝试将该电子邮件地址映射到作者表的数字 ID 列。

readBooksCsvData 方法，但我也根据您非常正确的假设更正了代码。稍后我会用更正的代码写一个答案。

如果我理解模型正确，你需要在Author类中修改以下2行（更改mappedBy）：@ManyToMany(mappedBy = "authors", fetch = FetchType.LAZY) List书籍； @ManyToMany(mappedBy = "authors", fetch = FetchType.LAZY) List 杂志；指向实体而不是元素集合

@osamayaccoub 为什么会这样？请解释

如果你想在作者和书以及作者和杂志之间实现双向多对多关系，mappedBy 应该引用 @ManyToMany 注释的元素而不是注释的元素由@ElementCollection

【参考方案1】：

根本问题是 CSV 文件使用电子邮件地址字符串作为作者 ID，但作者实体类被建模为使用数字序列 ID。我修改了如下代码，

@Entity
@Table(name = "Author")
public class Author implements Serializable 

    private static final long serialVersionUID = 1L;


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

    // email;firstname;lastname

    @Column
    private String firstname;

    @Column
    private String lastname;

    @ManyToMany(mappedBy = "bookAuthors", fetch = FetchType.LAZY)
    List<Book> books;

    @ManyToMany(mappedBy = "bookAuthors", fetch = FetchType.LAZY)
    List<Magazine> magazines;

    public Author() 

    

    public Author(String email, String firstname, String lastname) 
        this.email = email;
        this.firstname = firstname;
        this.lastname = lastname;
    

因此，代码现在可以正确读取和保存 CSV 文件中的数据了。