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我创建了一个 API，它被称为搜索商店功能。.

MySql 脚本

当我使用这个 SQL 脚本在 MySql 中运行时。它将显示有效结果

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;

.

点击图片查看MySQL的结果

MySQL 和有效结果图像

来自 StoreService.java 和 Hibernate 的日志

调用API前点击查看Postman

当我通过前端调用它时，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 调用 API 时的错误日志

邮递员参数图像
当邮递员调用它时会得到

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 代码：

StoreController.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;

}

.

StoreService.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);
}

.

StoreRepository.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 类中被标记为他们有来自javax.persistence包的@Table和@JoinColumn警告

Cannot resolve table 'table_name'在@Table和 @JoinColumnCannot resolve column 'product_id'
Cannot resolve column 'branch_id'中

Store.java (Pojo)

Product.java (Pojo)

Branch.java (Pojo)

我想知道根本原因

  1. 为什么我从 Frontend 调用 API 时得不到有效结果？
  2. 为什么我不能从 Postman 调用 API？
  3. 为什么javax.persistenct的注释无法解析table_name和column_name？

最后我需要解决这些问题的解决方案

非常感谢您的帮助

4

2 回答 2

0

我在我的实体类中被标记为他们从 javax.persistence 收到关于 @Table 的警告无法解析 @Table 中的表 'table_name' 并且无法解析列 'product_id' 无法解析 @JoinColumn 中的列 'branch_id'

这就是hibernate实际上不能映射表的原因，你需要先修复映射，所以hibernate知道要使用哪个表。目前它在不是您的商店或产品表的 sql 中寻找“table_name”。我们不知道您的映射是否正确，因为您的实体类代码未在此处共享，但很可能注释或 xml 文件的映射名称来自错误本身，最终导致整个请求崩溃。

编辑：请检查这些库是否包含在您的类路径中：hibernate-annotations.jar lib/hibernate-comons-annotations.jar lib/ejb3-persistence.jar

另外，我建议您使用休眠查询语言而不是本机查询，因为当您想要切换底层数据库时它们更具可扩展性。

根本原因是，hibernate 是数据库抽象层又名 DBAL，这个库的全部目的是代表您的代码构建查询并执行它们。您正在尝试将其用作本机 sql 包装器，并且 sql 查询会给 hibernate 提供结果，但是由于映射错误，它无法在您的实体中解析和存储数据，虽然它在某些情况下很有用，但 hibernate 本身提供了更强大的功能，例如延迟加载，实体关系等等。

您可以在此处阅读完整文档以使用此类功能。 入门指南

Hibernate 查询语言参考

于 2020-02-08T09:38:39.213 回答
0

我已经找到了如何修复 Postman 无法完成此 API 并且前端得到一个空数组的方法。

我只是添加@ToString(exclude = "stores")并@EqualsAndHashCode(exclude = "stores")进入具有多对多关联的实体。

实体中的当前代码是：

产品.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;
}

但我还不明白为什么它会出错。你能解释一下吗？

于 2020-02-09T09:54:09.687 回答