Question

假设我需要将两个对象映射为一个或一个对象映射为一个（重载）。我可以通过以下映射做到这一点：

@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);
}

请注意，默认情况下，第一个映射器将所有字段从源映射到目标（大多数字段名称匹配），但是有两个特定的映射，从源到名称不同的目标字段。

第二个映射器希望将thing的 all 映射到 root 目标中，就像第一个映射器一样，但是随后还要映射第二个参数{ {1}}到目标的同名owner字段。

是否可以更改第二个映射器“先执行第一个映射器”，然后应用owner的附加映射？

Answer 1

在这种情况下，您可以做的是使用自定义方法。

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;
    }
}

具有多个源的MapStruct映射器

1 个答案: