Spring JDBC的使用（一）

1.需要导入相关的依赖

    org.springframework.boot
    spring-boot-starter-jdbc


    mysql
    mysql-connector-java

2.数据源配置

#数据源配置
spring.datasource.url=jdbc:mysql://localhost:3308/test?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

3.建表

CREATE TABLE `book` (
  `book_id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键id',
  `book_name` varchar(32) DEFAULT NULL COMMENT '书名',
  `book_descript` varchar(32) DEFAULT NULL COMMENT '书本描述',
  `book_price` float(11) DEFAULT NULL COMMENT '书本价格',
  PRIMARY KEY (`book_id`)
) ENGINE=InnoDB AUTO_INCREMENT=102 DEFAULT CHARSET=utf8;

4.创建实体类

public class Book {
    private Long bookId;
    private String bookName;
    private String bookDescript;
    private float bookPrice;

    public Book(String bookName, String bookDescript, float bookPrice) {
        this.bookName = bookName;
        this.bookDescript = bookDescript;
        this.bookPrice = bookPrice;
    }

    public Long getBookId() {
        return bookId;
    }

    public String getBookName() {
        return bookName;
    }

    public String getBookDescript() {
        return bookDescript;
    }

    public float getBookPrice() {
        return bookPrice;
    }
}

5.封装Repository

public interface BookRepository {
    int save(Book book);
    int update(Book book);
    int delete(Long id);
    List findAll();
    Book findById(Long id);
}

6.创建Repository的实现类

其中findById方法和findAll的查询结果需要进行封装，其中findById使用了new BeanPropertyRowMapper(Book.class)对返回结果进行了封装，它可自动将一行数据映射到指定类的实例中，首先先将这个类实例化，然后通过名称匹配的方式，映射到属性中去。findAll方法的返回结果通过创建的内部类BookRowMapper进行封装。

@Repository
public class BookRepositoryImpl implements BookRepository {
    @Autowired
    private JdbcTemplate jdbcTemplate;
    @Override
    public int save(Book book) {
        return jdbcTemplate.update("insert into book(book_name,book_descript,book_price) value(?,?,?)",book.getBookName(),book.getBookDescript(),book.getBookPrice());
    }

    @Override
    public int update(Book book) {
        return 0;
    }

    @Override
    public int delete(Long id) {
        return 0;
    }

    @Override
    public List findAll() {
        return jdbcTemplate.query("select * from book",new BookRowMapper());
    }

    @Override
    public Book findById(Long id) {
        return jdbcTemplate.queryForObject("select * from book where book_id = ?",new Object[]{id},new BeanPropertyRowMapper(Book.class));
    }
}

class BookRowMapper implements RowMapper{

    @Override
    public Book mapRow(ResultSet resultSet, int i) throws SQLException {
        Book book = new Book();
        book.setBookId(resultSet.getLong("book_id"));
        book.setBookName(resultSet.getString("book_name"));
        book.setBookDescript(resultSet.getString("book_descript"));
        book.setBookPrice(resultSet.getFloat("book_price"));
        return book;
    }
}

7.测试

@SpringBootTest
class D8ApplicationTests {
    @Autowired
    private BookRepository bookRepository;  
    @Test
    void saveBook(){
        Book book = new Book("西游记","西游记是一本xxx的小说",36);
        bookRepository.save(book);
    }
    @Test
    void findBookById(){
        Long id = new Long(102);
        Book book = bookRepository.findById(id);
        System.out.println(book.getBookName());
        System.out.println(book.getBookDescript());
        System.out.println(book.getBookPrice());

    }

    @Test
    void findAll(){
        List bookList = bookRepository.findAll();
        System.out.println(bookList.get(0).getBookName());
    }
}

8.总结

感觉spring jdbc对结果集的处理不太好用