JPA check the manual that corresponds to your MySQL server version for the right syntax to use near

对于这个错误，您需要检查您的语法是否正确。请确保您使用的MySQL版本与您的JPA配置兼容，并且没有任何语法错误。

此外，还有一些常见的问题可能导致此错误：
1. 检查您的SQL语句是否正确，包括表名、列名和语法。
2. 确保您在查询中使用正确的引号和括号。
3. 检查您的JPA实体类和数据库表之间的映射是否正确。

如果问题仍然存在，请提供更多的详细信息，例如您的代码和完整的错误消息，以便我可以更好地帮助您。

相关问题

jpa2.2.10 Query 使用entityManager构建hql查询返回Dto，实体类和Dto中都有set<实体类>，写个有效的示例，避免这个问题 check the manual that corresponds to your MySQL server version for the right syntax to use near 'as col_9_0_, . as col_10_0_, . as col_11_0_ from user

我了解您的问题。以下是一个基本示例，演示如何使用entityManager构建hql查询返回Dto，实体类和Dto中都有set<实体类>。

假设您有一个名为User的实体类和一个名为UserDto的DTO类。User类有一个名为followers的Set<User>属性，而UserDto类也有一个名为followers的Set<UserDto>属性。

要使用entityManager构建hql查询返回UserDto对象，请按如下方式操作：

String hql = "SELECT NEW com.example.UserDto(u.id, u.username, u.email, u.password, u.followers) FROM User u WHERE u.username = :username";
TypedQuery<UserDto> query = entityManager.createQuery(hql, UserDto.class);
query.setParameter("username", "JohnDoe");
UserDto result = query.getSingleResult();

这里使用了一个特殊的语法，称为"SELECT NEW"，它允许您将查询结果直接映射到自定义的DTO类中。在这个例子中，我们使用UserDto类的构造函数来映射实体类User中的属性。

请注意，我们将实体类User中的Set<User>属性直接分配给UserDto中的Set<UserDto>属性。这是因为JPA会自动转换实体类和DTO类之间的关系，而不需要额外的转换代码。

总之，这是一个有效的示例，演示了如何使用entityManager构建hql查询返回Dto，并处理实体类和Dto中都有set<实体类>的情况。希望这可以回答您的问题！

implement the shipping REST APIs with spring boot + sping mvc + jpa/batis + mysql + jwt

Sure, here's an outline of how you can implement the shipping REST APIs using Spring Boot, Spring MVC, JPA/Batis, MySQL, and JWT:

1. Set up a Spring Boot project with the necessary dependencies for Spring MVC, JPA/Batis, MySQL, and JWT. You can use Spring Initializr to generate the project structure and add the dependencies.

2. Define the domain model for the shipping application, including entities such as Order, Product, Customer, and ShippingAddress. Map the entities to database tables using JPA annotations or MyBatis mapper XML files.

3. Implement the repository layer to perform CRUD operations on the database using JPA or MyBatis. You can use Spring Data JPA or MyBatis-Spring to simplify the implementation.

4. Define the REST API endpoints for the shipping application using Spring MVC annotations. Use JWT for authentication and authorization of the API endpoints.

5. Implement the service layer to perform business logic operations such as calculating shipping costs, validating orders, and processing payments. Use dependency injection to inject the repository and other services into the service layer.

6. Write unit tests to ensure that the application logic is working correctly. You can use JUnit and Mockito to write the tests.

7. Deploy the application to a server and test the API endpoints using a tool such as Postman.

Here's some example code to get you started:

@RestController
@RequestMapping("/api/orders")
public class OrderController {
    
    @Autowired
    private OrderService orderService;
    
    @PostMapping("/")
    public ResponseEntity<Order> createOrder(@RequestBody Order order) {
        Order createdOrder = orderService.createOrder(order);
        return ResponseEntity.ok(createdOrder);
    }
    
    @GetMapping("/{id}")
    public ResponseEntity<Order> getOrder(@PathVariable("id") Long orderId) {
        Order order = orderService.getOrder(orderId);
        return ResponseEntity.ok(order);
    }
    
    // Other API endpoints for updating and deleting orders
}

@Service
public class OrderService {
    
    @Autowired
    private OrderRepository orderRepository;
    
    public Order createOrder(Order order) {
        // Calculate shipping costs and validate the order
        order.setShippingCosts(10.0);
        order.setTotalPrice(order.getProducts().stream()
            .mapToDouble(Product::getPrice)
            .sum() + order.getShippingCosts());
        return orderRepository.save(order);
    }
    
    public Order getOrder(Long orderId) {
        return orderRepository.findById(orderId)
            .orElseThrow(() -> new NotFoundException("Order not found"));
    }
    
    // Other service methods for updating and deleting orders
}

@Repository
public interface OrderRepository extends JpaRepository<Order, Long> {
    
}

This code defines a REST API endpoint for creating orders and getting orders by ID. The order creation logic is implemented in the OrderService class, which calculates shipping costs and saves the order to the database using the OrderRepository interface. JWT authentication and authorization can be added to the API endpoints using Spring Security.