Spring JPA查詢以獲取具有計數條件的數據

Question

我有一個具有許多審閱實體的訂單實體。 訂單具有許多OrderItem實體，也具有許多審閱實體。 因此，用戶可以將特定訂單的評論輸入為普通評論，也可以將特定訂單商品輸入為商品評論。

現在，我要列出具有可用評論的訂單和沒有評論的訂單。 為此，我必須檢查訂單|| OrderItem在評論表中同時具有評論。 我認為要執行帶有Join子句的計數查詢。 請解決這個問題。

OrderDO.java

@Table(name = "ORDER")
public class OrderDO  implements Serializable{

    @Column(name = "ORDER_NUMBER", nullable = false)
    private String orderNumber; 

    @OneToMany(cascade = CascadeType.ALL, mappedBy="order")
    private Set<ReviewDO> reviews = new HashSet<>();
}

OrderItemDO.java

@Table(name = "ORDER_ITEM")
public class OrderItemDO implements Serializable{   

    @Column(name = "PRODUCT_NAME",nullable = false)
    private String name;

    @OneToMany(cascade = CascadeType.ALL, mappedBy="item")
    private Set<ReviewDO> reviews = new HashSet<>();
}

ReviewDO.java

@Table(name = "REVIEW")
public class ReviewDO implements Serializable {

    @Column(name = "RATING")
    private double rating;

    @Column(name = "REVIEW_TEXT")
    private String reviewText;

    @ManyToOne()
    @JoinColumn(name = "ITEM_ID", referencedColumnName="ID")
    private OrderItemDO item;

    @ManyToOne()
    @JoinColumn(name = "ORDER_ID", referencedColumnName="ID")
    private OrderDO order;
   }

OrderRepository.java

@Repository
public interface OrderRepository extends CrudRepository<OrderDO, Long>{

    @Query("select order from OrderDO order where order.orderNumber = ?1")
    public Optional<OrderDO> findByOrderNumber(String orderNumber);

}

Answer 1

要查找與訂單或訂單項關聯的評論，可以通過放置一個ReviewRepository來對ReviewDO對象進行查詢，如下所示：

@Repository
public interface ReviewRepository extends CrudRepository<ReviewDO, Long>{

    @Query(value = "SELECT r FROM ReviewDO r where r.item is not null or r.order is not null")
    List<ReviewDO> findAllByOrdersOrOrderItems();

}

請檢查下面給出的測試用例是否符合您的要求

導入靜態org.junit.Assert.assertEquals;

import java.util.List;
import java.util.stream.Collectors;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import com.raj.so.artefacts.OrderDO;
import com.raj.so.artefacts.OrderItemDO;
import com.raj.so.artefacts.OrderItemRepository;
import com.raj.so.artefacts.OrderRepository;
import com.raj.so.artefacts.ReviewDO;
import com.raj.so.artefacts.ReviewRepository;

@DataJpaTest
@RunWith(SpringRunner.class)
public class ReviewRepositoryTest {

    @Autowired
    private OrderRepository orderRepository;

    @Autowired
    private OrderItemRepository orderItemRepository;

    @Autowired
    private ReviewRepository reviewRepository;

    @Test
    public void testRepositoryFetch() {

        // creating 2 orders
        OrderDO orderDO1 = new OrderDO();
        orderDO1.setOrderNumber("1");
        orderRepository.save(orderDO1);
        OrderDO orderDO2 = new OrderDO();
        orderDO2.setOrderNumber("2");
        orderRepository.save(orderDO2);

        // creating an order item
        OrderItemDO orderItemDO1 = new OrderItemDO();
        orderItemDO1.setName("order item 1");
        orderItemRepository.save(orderItemDO1);

        // creating 2 reviews - one for order; other for item
        ReviewDO reviewDO1 = new ReviewDO();
        reviewDO1.setRating(5.0);
        reviewDO1.setReviewText("rate five");
        reviewDO1.setOrder(orderDO1);
        reviewRepository.save(reviewDO1);

        ReviewDO reviewDO2 = new ReviewDO();
        reviewDO2.setRating(4.0);
        reviewDO2.setReviewText("rate four");
        reviewDO2.setItem(orderItemDO1);
        reviewRepository.save(reviewDO2);

        // query all reviews associated to orders or items
        // returned review objects will have details about orders and items
        List<ReviewDO> reviews = reviewRepository.findAllByOrdersOrOrderItems();

        assertEquals(2, reviews.size());

        List<String> orderNumbers = reviews.stream().map(item -> {
            if (item.getOrder() != null) {
                return item.getOrder().getOrderNumber();
            } else {
                return null;
            }
        })
        .filter(item -> item != null)
        .collect(Collectors.toList());

        assertEquals("1", orderNumbers.get(0));

        List<String> orderItemNames = reviews.stream().map(item -> {
            if (item.getItem() != null) {
                return item.getItem().getName();
            } else {
                return null;
            }
        })
        .filter(item -> item != null)
        .collect(Collectors.toList());

        assertEquals("order item 1", orderItemNames.get(0));
    }
}