Java 如何使用模型映射器映射修改的、不匹配目标、源值？

我有两个API实体（

EntityA

和

EntityB

）实现了

BaseEntity

。 两个实体都具有可为空的参数

标识符

@Value
@Builder(builderClassName = "Builder")
public class EntityA implements BaseEntity {
    String identifier;
...
}

我还有POJO和

externalId

参数。此字段值应包括源标识符的4个字符的前缀

@Data
@ToString(callSuper = true)
@EqualsAndHashCode(callSuper = true)
public class Pojo {
    private String externalId;
    ...
}

我想使用

ModelMapper

将API值映射到现有的POJO

PojoEntity

。但是,

源getter和目标setter不匹配

应修改源的值

我可以在已映射的POJO上设置值post factum

public Pojo mapEntityAToPojo(EntityA entity, Pojo pojo) {
    modelMapper.map(entity, pojo);
    Optional.ofNullable(entity.getIdentifier()).ifPresent(
            identifier -> pojo.setExternalId(getIdentifierAlphaNumericPrefix(identifier)));
    return pojo;
}

public Pojo mapEntityBToPojo(EntityB entity, Pojo pojo) {
    modelMapper.map(entity, pojo);
    Optional.ofNullable(entity.getIdentifier()).ifPresent(
            identifier -> pojo.setExternalId(getIdentifierAlphaNumericPrefix(identifier)));
    return pojo;
}

private String getIdentifierAlphaNumericPrefix(String identifier) {
    return identifier.replaceAll("[^a-zA-Z0-9]", "").substring(0, 4);
}

但我确信，有一种更优雅的方式来配置模型映射器。
有什么建议吗

public Pojo mapEntityAToPojo(EntityA entity, Pojo pojo) {
    modelMapper.map(entity, pojo);
    Optional.ofNullable(entity.getIdentifier()).ifPresent(
            identifier -> pojo.setExternalId(getIdentifierAlphaNumericPrefix(identifier)));
    return pojo;
}

public Pojo mapEntityBToPojo(EntityB entity, Pojo pojo) {
    modelMapper.map(entity, pojo);
    Optional.ofNullable(entity.getIdentifier()).ifPresent(
            identifier -> pojo.setExternalId(getIdentifierAlphaNumericPrefix(identifier)));
    return pojo;
}

private String getIdentifierAlphaNumericPrefix(String identifier) {
    return identifier.replaceAll("[^a-zA-Z0-9]", "").substring(0, 4);
}