自定义MonetaryAmount类型引发Hibernate ConversionException问题咨询

环境 #

• Spring Boot & Spring JPA 3.2.4
• Hibernate 6.4.4
• PostgreSQL

自定义类型与JPA配置 #

我自定义了MonetaryAmount类，内部封装了javax.money.MonetaryAmount和BigDecimal：

public class MonetaryAmount extends Number implements Comparable<MonetaryAmount> {
   ...
}

将该类作为JPA实体字段类型使用，并搭配实现AttributeConverter<MonetaryAmount, BigDecimal>的MonetaryAmountConverter转换器：

@Convert(converter = MonetaryAmountConverter.class)
@Column(name = "total_amount")
private MonetaryAmount totalAmount = ZERO;

@Convert(converter = MonetaryAmountConverter.class)
@Column(name = "amount_raised")
private MonetaryAmount amountRaised = ZERO;

PostgreSQL数据库中对应列的类型为numeric(20,2)。

问题场景与异常 #

编写Spring JPA查询时，若左侧两个自定义类型字段使用+、-、*或/数学运算符进行运算，右侧使用单个数字字面量，例如：

@Query(value = "SELECT l FROM Loan l where l.amountRaised + l.totalAmount >= 2 ")

会触发Hibernate异常：

Caused by: org.hibernate.query.sqm.sql.ConversionException: Could not determine ValueMapping for SqmExpression: org.hibernate.query.sqm.tree.expression.SqmBinaryArithmetic@55bc8579
    at app//org.hibernate.query.sqm.sql.BaseSqmToSqlAstConverter.determineValueMapping(BaseSqmToSqlAstConverter.java:5872)
    at app//org.hibernate.query.sqm.sql.BaseSqmToSqlAstConverter.lambda$visitComparisonPredicate$111(BaseSqmToSqlAstConverter.java:7524)
at app//org.hibernate.query.sqm.sql.BaseSqmToSqlAstConverter.visitHqlNumericLiteral(BaseSqmToSqlAstConverter.java:5583)
...

尝试使用2.0或2BD替代2，问题依然存在。但如果右侧改为两个数字字面量的运算（例如2 * 1），查询就能正常运行：

@Query(value = "SELECT l FROM Loan l where l.amountRaised + l.totalAmount >= 2 * 1")

疑问 #

这是Hibernate的缺陷（已提交缺陷工单HHH-17899），还是我的自定义类需要调整？

内容的提问来源于stack exchange，提问作者Sunil