从 Hibernate Native 查询接收到不准确（且令人困惑）的错误 [重复]

Question

我不明白为什么会出现此错误：

java.lang.NullPointerException：无法调用 “String.toLowerCase(java.util.Locale)”因为“columnName”为空

这是我数据库中的产品表：

这是产品型号：

@Entity
@Table(name = "product", schema = "auction_app_schema")
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Product {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

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

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

    @Column(name = "start_price", nullable = false)
    private Float startPrice;

    @ElementCollection
    @CollectionTable(name = "product_images", joinColumns = @JoinColumn(name = "product_id"))
    @Column(name = "image")
    private List<String> images;

    @Column(name = "start_date", nullable = false)
    private LocalDateTime startDate;

    @Column(name = "end_date", nullable = false)
    private LocalDateTime endDate;

    @Formula("(SELECT COUNT(*) FROM auction_app_schema.bid b INNER JOIN auction_app_schema.product p ON p.id = b.product_id WHERE b.product_id = p.id)")
    private BigInteger numberOfBids;

    @Formula("(SELECT b.price FROM auction_app_schema.product p INNER JOIN auction_app_schema.bid b ON p.id =b.product_id ORDER BY b.price DESC LIMIT 1)")
    private BigDecimal highestBid;

    @ManyToOne
    @JoinColumn(name = "category_id", nullable = false)
    private Category category;
}

这是存储库功能：

@Query(value = "SELECT p.id, p.description, p.product_name, p.start_price, p.start_date, p.end_date, p.category_id, p.is_highlighted, pi.image\n" +
        "FROM auction_app_schema.product p\n" +
        "INNER JOIN auction_app_schema.category c ON p.category_id = c.id\n" +
        "INNER JOIN auction_app_schema.product_images pi ON p.id = pi.product_id\n" +
        "WHERE c.id = ? LIMIT ? OFFSET ?", nativeQuery = true)
List<Product> findProductsByCategoryId(Long categoryId, int limit, int offset);

上下文：直接在数据库中执行的相同查询有效，当我向服务器发送请求时，即使我在数据库中拥有所有列，我也会得到

NullPointerException

。直到现在我才在 PostgreSQL 中遇到这个问题。我认为 Hibernate 只是没有接受我的架构。

这几乎是整个堆栈跟踪：

FROM auction_app_schema.product p
INNER JOIN auction_app_schema.category c ON p.category_id = c.id
INNER JOIN auction_app_schema.product_images pi ON p.id = pi.product_id
WHERE c.id = ? LIMIT ? OFFSET ?
2023-04-01 22:56:55.147 ERROR 18404 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException: Cannot invoke "String.toLowerCase(java.util.Locale)" because "columnName" is null] with root cause

    java.lang.NullPointerException: Cannot invoke "String.toLowerCase(java.util.Locale)" because "columnName" is null
        at org.postgresql.jdbc.PgResultSet.findColumnIndex(PgResultSet.java:2791) ~[postgresql-42.2.23.jar:42.2.23]
        at org.postgresql.jdbc.PgResultSet.findColumn(PgResultSet.java:2750) ~[postgresql-42.2.23.jar:42.2.23]
        at org.postgresql.jdbc.PgResultSet.getBigDecimal(PgResultSet.java:410) ~[postgresql-42.2.23.jar:42.2.23]
        at com.zaxxer.hikari.pool.HikariProxyResultSet.getBigDecimal(HikariProxyResultSet.java) ~[HikariCP-4.0.3.jar:na]
        at org.hibernate.type.descriptor.sql.DecimalTypeDescriptor$2.doExtract(DecimalTypeDescriptor.java:63) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.type.descriptor.sql.BasicExtractor.extract(BasicExtractor.java:47) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:257) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:253) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:243) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.type.AbstractStandardBasicType.hydrate(AbstractStandardBasicType.java:329) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.persister.entity.AbstractEntityPersister.hydrate(AbstractEntityPersister.java:3131) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.loadFromResultSet(Loader.java:1863) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.hydrateEntityState(Loader.java:1791) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.instanceNotYetLoaded(Loader.java:1764) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.getRow(Loader.java:1616) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:740) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.getRowsFromResultSet(Loader.java:1039) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.processResultSet(Loader.java:990) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.doQuery(Loader.java:959) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:349) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.doList(Loader.java:2843) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.doList(Loader.java:2825) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2657) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.Loader.list(Loader.java:2652) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:338) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.internal.SessionImpl.listCustomQuery(SessionImpl.java:2141) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.internal.AbstractSharedSessionContract.list(AbstractSharedSessionContract.java:1169) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.query.internal.NativeQueryImpl.doList(NativeQueryImpl.java:176) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.query.internal.AbstractProducedQuery.list(AbstractProducedQuery.java:1604) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.hibernate.query.Query.getResultList(Query.java:165) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
        at org.springframework.data.jpa.repository.query.JpaQueryExecution$CollectionExecution.doExecute(JpaQueryExecution.java:126) ~[spring-data-jpa-2.5.5.jar:2.5.5]
        at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:88) ~[spring-data-jpa-2.5.5.jar:2.5.5]
        at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:155) ~[spring-data-jpa-2.5.5.jar:2.5.5]
        at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:143) ~[spring-data-jpa-2.5.5.jar:2.5.5]

Answer 1

看起来这表明您正在尝试对 null 调用“toLowerCase()”方法。

调用toLowerCase()方法前请确保columnName不为null。

您可以首先检查columnName是否为空，如果不为空，则分配小写版本。