spring框架mysql数据库操作

@Configuration
public class DataSourceConfig {
    @Bean
    public DataSource dataSource() {
        HikariDataSource dataSource = new HikariDataSource();
        dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/mydb");
        dataSource.setUsername("username");
        dataSource.setPassword("password");
        dataSource.setMaximumPoolSize(20); // 根据实际情况调整
        return dataSource;
    }
}

@Repository
public class UserDao {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    public User findUserById(int id) {
        String sql = "SELECT * FROM users WHERE id = :id";
        Map<String, Object> params = new HashMap<>();
        params.put("id", id);
        return jdbcTemplate.queryForObject(sql, params, User.class);
    }
}

@Service
public class UserService {
    @Autowired
    private UserDao userDao;

    @Transactional
    public void transfer(int fromId, int toId, double amount) {
        userDao.withdraw(fromId, amount);
        userDao.deposit(toId, amount);
    }
}