Spring boot 3 問題：為什么不能用Postman和Frontend調用API調用API然后得到空數組？

Question

我創建了一個 API，它被稱為搜索商店功能。 .

MySql 腳本

當我使用此 SQL 腳本在 MySql 中運行時。 它將顯示有效結果

SET @productName = null;
SET @BranchName = null;
SET @minPrice = 0;
SET @maxPrice = 10000;
SET @quantity = 1000;

SELECT * FROM stores s 
INNER JOIN products p 
ON p.id = s.product_id 
INNER JOIN branches b 
ON b.id = s.branch_id 
WHERE (p.name LIKE CONCAT('%', @productName , '%') OR @productName IS NULL) 
  AND (b.name LIKE  CONCAT('%', @branchName , '%')  OR @branchName IS NULL) 
  AND (@minPrice <= p.price AND p.price <= @maxPrice) 
  AND s.quantity <= @quantity 
ORDER BY p.name, b.name, quantity;

.

點擊圖片查看MySQL運行結果

MySQL 和有效的結果圖像

從 StoreService.java 和 Hibernate 登錄

調用API前點擊查看Postman

當我通過前端調用它時， StoreService.java 中的日志是...

productName: null, minPrice: 0.0, maxPrice: 15000.0, branchName: null, 1000
Hibernate: SELECT * FROM stores s INNER JOIN products p ON p.id = s.product_id INNER JOIN branches b ON b.id = s.branch_id WHERE (p.name LIKE CONCAT('%', ? , '%') OR ? IS NULL)  AND (b.name LIKE  CONCAT('%', ? , '%')  OR ? IS NULL)  AND (? <= p.price AND p.price <= ?)  AND s.quantity <= ?  ORDER BY p.name
Stores: []

.

Postman 調用 API 時的錯誤日志

郵遞員參數圖像
當郵遞員調用它時會得到

java.lang.StackOverflowError: null
    at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:944) ~[mysql-connector-java-8.0.19.jar:8.0.19]
    at com.mysql.cj.jdbc.ClientPreparedStatement.executeQuery(ClientPreparedStatement.java:1003) ~[mysql-connector-java-8.0.19.jar:8.0.19]
    at com.zaxxer.hikari.pool.ProxyPreparedStatement.executeQuery(ProxyPreparedStatement.java:52) ~[HikariCP-3.4.2.jar:na]
    at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.executeQuery(HikariProxyPreparedStatement.java) ~[HikariCP-3.4.2.jar:na]
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:57) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.getResultSet(AbstractLoadPlanBasedLoader.java:390) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeQueryStatement(AbstractLoadPlanBasedLoader.java:163) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:104) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.loader.collection.plan.AbstractLoadPlanBasedCollectionInitializer.initialize(AbstractLoadPlanBasedCollectionInitializer.java:87) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:707) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.event.internal.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:76) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:108) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.internal.SessionImpl.initializeCollection(SessionImpl.java:2145) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.collection.internal.AbstractPersistentCollection$4.doWork(AbstractPersistentCollection.java:589) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:264) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:585) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:149) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.collection.internal.PersistentSet.hashCode(PersistentSet.java:458) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at com.g_able.back_g_exam.entity.Product.hashCode(Product.java:12) ~[classes/:na]
    at com.g_able.back_g_exam.entity.Store.hashCode(Store.java:13) ~[classes/:na]
    at java.util.HashMap.hash(HashMap.java:339) ~[na:1.8.0_172]
    at java.util.HashMap.put(HashMap.java:612) ~[na:1.8.0_172]
    at java.util.HashSet.add(HashSet.java:220) ~[na:1.8.0_172]
    at java.util.AbstractCollection.addAll(AbstractCollection.java:344) ~[na:1.8.0_172]
    at org.hibernate.collection.internal.PersistentSet.endRead(PersistentSet.java:355) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.engine.loading.internal.CollectionLoadContext.endLoadingCollection(CollectionLoadContext.java:239) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.engine.loading.internal.CollectionLoadContext.endLoadingCollections(CollectionLoadContext.java:224) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.engine.loading.internal.CollectionLoadContext.endLoadingCollections(CollectionLoadContext.java:198) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.loader.plan.exec.process.internal.CollectionReferenceInitializerImpl.endLoading(CollectionReferenceInitializerImpl.java:154) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.loader.plan.exec.process.internal.AbstractRowReader.finishLoadingCollections(AbstractRowReader.java:267) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]
    at org.hibernate.loader.plan.exec.process.internal.AbstractRowReader.finishUp(AbstractRowReader.java:218) ~[hibernate-core-5.4.10.Final.jar:5.4.10.Final]

.

我的 Springboot 代碼：

存儲控制器.java

@GetMapping("/api/v1/stores/advance-search")
  public List<Store> findStoresByFilter(
      @RequestParam(required = false) String productName, @RequestParam(required = false) String branchName,
      @RequestParam(required = false, defaultValue = "0") Integer minPrice,
      @RequestParam(required = false, defaultValue = "999999") Integer maxPrice,
      @RequestParam(required = false, defaultValue = "3000") Integer quantity) {

    ProductParams productParams = ProductParams.builder().name(productName).minPrice(minPrice).maxPrice(maxPrice).build();
    Branch branch = Branch.builder().name(branchName).build();

    List<Store> stores = storeService.findStoresByFilter(productParams, branch, quantity);
    System.out.println("Stores: " + stores);
    return stores;

}

.

商店服務.java

public List<Store> findStoresByFilter(ProductParams productParams, Branch branch, int quantity) {
    System.out.println("productName: " + productParams.getName() + ", minPrice: " + productParams.getMinPrice() + ", maxPrice: "
        + productParams.getMaxPrice() + ", branchName: " + branch.getName() + ", " + quantity);
    return storeRepository.searchStoresByFilter(productParams.getName(), branch.getName(),
        productParams.getMinPrice(), productParams.getMaxPrice(), quantity);
}

.

存儲庫.java

@Query(nativeQuery = true,
      value = "SELECT * " +
          "FROM stores s " +
          "INNER JOIN products p " +
          "ON p.id = s.product_id " +
          "INNER JOIN branches b " +
          "ON b.id = s.branch_id " +
          "WHERE (p.name LIKE CONCAT('%', :productName , '%') OR :productName IS NULL) " +
          " AND (b.name LIKE  CONCAT('%', :branchName , '%')  OR :branchName IS NULL) " +
          " AND (:minPrice <= p.price AND p.price <= :maxPrice) " +
          " AND s.quantity <= :quantity " +
          " ORDER BY p.name")
  List<Store> searchStoresByFilter(@Param("productName") String productName, @Param("branchName") String branchName,
                                 @Param("minPrice") double minPrice, @Param("maxPrice") double maxPrice, @Param("quantity") int quantity);

注意：

我在我的POJO 類中被標記，他們對javax.persistence包中的@Table和@JoinColumn發出警告

Cannot resolve table 'table_name' @Table 中的Cannot resolve table 'table_name'並且Cannot resolve column 'product_id'
Cannot resolve column 'branch_id'在@JoinColumn

Store.java (Pojo)

Product.java (Pojo)

Branch.java (Pojo)

我想知道根本原因

1. 為什么從前端調用 API 時得不到有效結果？
2. 為什么我不能從 Postman 調用 API？
3. 為什么來自javax.persistenct 的注解無法解析table_name和column_name ？

最后我需要解決這些問題的解決方案

非常感謝您的幫助

Answer 1

我在我的實體類中被標記，他們有來自 javax.persistence 的關於 @Table 的警告無法解析 @Table 中的表 'table_name' 並且無法解析列 'product_id' 無法解析 @JoinColumn 中的列 'branch_id'

這就是 hibernate 不能真正映射表的原因，你需要先修復映射，所以 hibernate 知道要使用哪個表。 目前它在 sql 中尋找“table_name”，這不是您的商店或產品表。 我們不知道您的映射是否正確，因為您的實體類代碼未在此處共享，但注釋或 xml 文件可能具有錯誤本身的錯誤映射名稱，最終導致整個請求崩潰。

編輯：請檢查這些庫是否包含在您的類路徑中：hibernate-annotations.jar lib/hibernate-comons-annotations.jar lib/ejb3-persistence.jar

此外，我建議您使用休眠查詢語言而不是本機查詢，因為當您想要切換基礎數據庫時，它們的可擴展性要高得多。

根本原因是，hibernate 是數據庫抽象層又名 DBAL，該庫的全部目的是代表您的代碼構建查詢並執行它們。 您正在嘗試將其用作本機 sql 包裝器，並且 sql 查詢會將結果提供給 hibernate，但由於映射錯誤，因此無法在實體中解析和存儲數據，雖然它在某些情況下很有用，但 hibernate 本身提供了更強大的功能，例如延遲加載、實體關系等等。

您可以在此處閱讀完整文檔以使用此類功能。 入門指南

Hibernate 查詢語言參考

Answer 2

我已經找到了如何修復 Postman 無法完成此 API 並且前端獲得空數組的方法。

我只是將@ToString(exclude = "stores")和@EqualsAndHashCode(exclude = "stores")到具有多對多關聯的實體中。

實體中的當前代碼是：

產品.java

@Data
@ToString(exclude = "stores")
@EqualsAndHashCode(exclude = "stores")
@NoArgsConstructor
@AllArgsConstructor
@Entity
@Table(name = "products")
@Builder(toBuilder = true)
public class Product {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Integer id;

  @Column(nullable = false, length = 50)
  private String name;

  private String detail;

  private double price;

  @JsonIgnore
  @OneToMany(mappedBy = "product")
  private Set<Store> stores;

}

分支.java

@Data
@ToString(exclude = "stores")
@EqualsAndHashCode(exclude = "stores")
@NoArgsConstructor
@AllArgsConstructor
@Entity
@Table(name = "branches")
@Builder(toBuilder = true)
public class Branch {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Integer id;

  @Column(nullable = false, length = 60)
  private String name;

  @JsonIgnore
  @OneToMany(mappedBy = "branch")
  private Set<Store> stores;
}

但我不明白為什么它會出錯。 你能解釋一下嗎？