多源MapStruct映射器

Question

假设我需要将两个对象映射成一个或一个对象映射成一个（重载）。我可以通过以下映射来实现：

@Mapper
public interface ThingMapper
{
    @Mappings(
        {
            @Mapping(source = "createdDateTime", target = "thingDate"),
            @Mapping(source = "approver.id", target = "approverId"),
        })
    ThingEventPayload toEventPayload(Thing thing);

    // TODO this is redundant, how to clean up?
    @Mappings(
        {
            // since there are two params, need to specifically map same-named params from source "thing" to target
            @Mapping(source = "thing.id", target = "id"),
            @Mapping(source = "thing.deletedDateTime", target = "deletedDateTime"),
            @Mapping(source = "thing.version", target = "version"),
            @Mapping(source = "thing.autoApproved", target = "autoApproved"),
            @Mapping(source = "thing.resolvedDate", target = "resolvedDate"),
            @Mapping(source = "thing.status", target = "status"),

            // numerous other fields mapping from source "thing" to target with same property name

            // map differently named parameters (duplicate of other mapper, above)
            @Mapping(source = "thing.createdDateTime", target = "thingDate"),
            @Mapping(source = "thing.approver.id", target = "approverId"),

            // mapping second parameter "owner" directory to target "owner" property
            @Mapping(source = "owner", target = "owner"),
        })
    ThingEventPayload toEventPayload(Thing thing, User owner);
}

是否有一种方法可以更改第二个映射器“先做第一个映射器”，然后应用@mapping(source=“owner”,target=“owner”）的附加映射？

Answer 1

在这种情况下，您可以使用自定义方法。

例如

@Mapper
public interface ThingMapper {
    @Mappings(
        {
            @Mapping(source = "createdDateTime", target = "thingDate"),
            @Mapping(source = "approver.id", target = "approverId"),
        })
    ThingEventPayload toEventPayload(Thing thing);

    UserPayload toUserPayload(User user);

    default ThingEventPayload toEventPayload(Thing thing, User owner) {
        ThingEventPayload eventPayload = toEventPayload(thing);
        if (eventPayload != null) {
            eventPayload.setOwner(toUserPayload(owner));
        }
        return eventPayload;
    }
}