我正在使用 Lombok，我需要一种方法来自动设置子类中父类(super class)字段的值，无需重新声明。

It is working fine on its own (@SuperBuiler and @Builder.Default) when using the builder, but it is giving troubles with Spring-Data MongoDB.

org.springframework.data.mapping.MappingException: Ambiguous field mapping detected! Both protected test.jackson.polymorphism.domain.enumeration.EvaluationType test.jackson.polymorphism.domain.models.EvaluationModel.type and private test.jackson.polymorphism.domain.enumeration.EvaluationType test.jackson.polymorphism.domain.models.QuantitativeEvaluationModel.type map to the same field name type! Disambiguate using @Field annotation!

    at org.springframework.data.mongodb.core.mapping.BasicMongoPersistentEntity$AssertFieldNameUniquenessHandler.assertUniqueness(BasicMongoPersistentEntity.java:368)
    at org.springframework.data.mongodb.core.mapping.BasicMongoPersistentEntity$AssertFieldNameUniquenessHandler.doWithPersistentProperty(BasicMongoPersistentEntity.java:354)
    at org.springframework.data.mongodb.core.mapping.BasicMongoPersistentEntity$AssertFieldNameUniquenessHandler.doWithPersistentProperty(BasicMongoPersistentEntity.java:348)

这些是我的类(class):

public enum EvaluationType{
    QUALITATIVE, QUANTITATIVE;
}

@Data
@SuperBuilder
@NoArgsConstructor
@AllArgsConstructor
public abstract class EvaluationModel {
    protected EvaluationType type;
    protected Integer evaluation;
}

@Data
@SuperBuilder
@NoArgsConstructor
@AllArgsConstructor
public class QualitativeEvaluationModel extends EvaluationModel {
    /**
     * How to set the default value for this field
     * without redeclaring it?
     */
    @Builder.Default
    private EvaluationType type = EvaluationType.QUALITATIVE;
}

@Data
@SuperBuilder
@NoArgsConstructor
@AllArgsConstructor
public class QuantitativeEvaluationModel extends EvaluationModel {
    /**
     * How to set the default value for this field
     * without redeclaring it?
     */
    @Builder.Default
    private EvaluationType type = EvaluationType.QUANTITATIVE;

    @Builder.Default
    private String currencyCode = Currency.getInstance("EUR").getCurrencyCode();

    private BigDecimal economicValue;
}

如何使这些子类的 type 字段具有默认值(可能是最终值)，但不重新声明该字段？ 这应该适用于构造函数和构建器。

最佳答案

解决此问题(并非特定于 Lombok)的解决方案是在子类中使用初始化 block ( https://docs.oracle.com/javase/tutorial/java/javaOO/initial.html)。

@Data
@SuperBuilder
public class QualitativeEvaluationModel extends EvaluationModel {
    {
        super.type = EvaluationType.QUALITATIVE;
    }
}

关于java - Lombok 继承 : how to set default value for field in superclass without redeclaring it?，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/70868565/