我们有时在进行开发过程中,使用jpa的@Query注解去选择多张表然后返回一个DTO对象,这个时候我们需要特殊处理一下,因为默认情况下,你的jpa代码是不认DTO对象的。
参考文章:https://smarterco.de/spring-data-jpa-query-result-to-dto/
@Entity @Getter @Setter @Builder @ToString @AllArgsConstructor @NoArgsConstructor public class OrderInfo extends EntityBase { @Id @GeneratedValue private int id; private int userId; private String userName; private double total; private String shippingName; private String shippingAddress; private Date orderTime; } @Entity @Getter @Setter @Builder @ToString @AllArgsConstructor @NoArgsConstructor public class OrderItem extends EntityBase { @Id @GeneratedValue private int id; private int orderId; private int productId; private String productName; private int count; private double salePrice; } /** * DTO对象 */ @Getter @Setter @Builder @ToString @AllArgsConstructor @NoArgsConstructor public class OrderList { public int id; private int userId; private String userName; private int productId; private String productName; private int count; private double salePrice; }
@Query("select new com.lind.microservice.productCenter.dto.OrderList" + "( o.id,o.userId,o.userName,oi.productId,oi.productName,oi.count,oi.salePrice) " + " from OrderInfo o " + " join OrderItem oi on o.id=oi.orderId") List<OrderList> getOrderInfos();
[ { "id": 5, "userId": 3, "userName": "lind", "productId": 4, "productName": "足球", "count": 1, "salePrice": 99 } ]