java我正试图使用Datastax 4.2.2编写DAO接口，但出现了几个编译错误

Question

我有以下几点建议：

@Table(name = "order", readConsistency = "QUORUM", writeConsistency = "QUORUM")
public class Order {    
    
    @Column(name = "id")
    @PartitionKey
    private String id;

    @Column(name = "customer_id")
    private String customerId;

    @Column(name = "loyalty_id")
    private String loyaltyId;

    @Column(name = "customer_email")
    private String customerEmail;

    public Order() {

    }
    ... getters and setters
}

现在，我正在编写OrderDao，如下所示：

    import com.datastax.oss.driver.api.mapper.annotations.*;

    @Dao
    public interface OrderDao {
            @Select
            Order findById(String orderId);

            @Insert
            void save(Order order);

            @Delete
            void delete(Order order);
    }

当我做./gradlew build时，我会得到以下错误：

error: Invalid return type: Select methods must return one of [ENTITY, OPTIONAL_ENTITY, FUTURE_OF_ENTITY, FUTURE_OF_OPTIONAL_ENTITY, PAGING_ITERABLE, FUTURE_OF_ASYNC_PAGING_ITERABLE]
    Order findById(String orderId);

error: Insert methods must take the entity to insert as the first parameter
    void save(Order order);
         ^

error: Missing entity class: Delete methods that do not operate on an entity instance must have an 'entityClass' argument
    void delete(Order order);
         ^

我通过以下文档实现：https://docs.datastax.com/en/developer/java-driver/4.2/manual/mapper/。可能的原因是什么

谢谢

Answer 1

在Order类上缺少@Entity注释：

@Entity
@Table(name = "order", readConsistency = "QUORUM", writeConsistency = "QUORUM")
public class Order {