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问Mapstruct -将属性映射到列表中对象的属性
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Stack Overflow用户

提问于 2022-06-08 16:08:24

回答 1查看 652关注 0票数 2

你好，我有以下课程：

public class BookWriteModel {
    List<PageWriteModel> pages;
}

public class Book {
    List<Page> pages;
}

public class PageWriteModel {
    Long pageNumber;
}

public class Page {
    Long pageNumber;
    Long userId;
}

public class User {
    Long userId;
}

我现在的地图是这样的：

@Mapper( componentModel = "spring", unmappedTargetPolicy = ReportingPolicy.IGNORE )
public interface BookMapper {
    Book map(BookWriteModel bookWriteModel, User user);
}

将userId映射到页面上的userId的更简单的方法是什么？

谢谢

java

mapstruct

回答 1

Stack Overflow用户

发布于 2022-06-09 00:30:10

解决方案1: @AfterMapping method

@Mapper( componentModel = "spring", unmappedTargetPolicy = ReportingPolicy.IGNORE )
public interface BookMapper {
    BookMapper INSTANCE = Mappers.getMapper(BookMapper.class);

    Book map(BookWriteModel bookWriteModel, User user);

    @AfterMapping
    default void afterMap(@MappingTarget Book book, User user) {
        if (user != null) {
            for (Page page : book.pages) {
                page.userId = user.userId;
            }
        }
    }
}

生成的代码：

@Component
public class BookMapperImpl implements BookMapper {
    @Override
    public Book map(BookWriteModel bookWriteModel, User user) {
        if ( bookWriteModel == null && user == null ) {
            return null;
        }
        Book book = new Book();
        if ( bookWriteModel != null ) {
            book.pages = pageWriteModelListToPageList( bookWriteModel.pages );
        }
        afterMap( book, user );
        return book;
    }

    protected Page pageWriteModelToPage(PageWriteModel pageWriteModel) {
        if ( pageWriteModel == null ) {
            return null;
        }
        Page page = new Page();
        page.pageNumber = pageWriteModel.pageNumber;
        return page;
    }

    protected List<Page> pageWriteModelListToPageList(List<PageWriteModel> list) {
        if ( list == null ) {
            return null;
        }
        List<Page> list1 = new ArrayList<Page>( list.size() );
        for ( PageWriteModel pageWriteModel : list ) {
            list1.add( pageWriteModelToPage( pageWriteModel ) );
        }
        return list1;
    }
}

解决方案2:使用 @上下文 来收集 @ObjectFactory

@Mapper( componentModel = "spring", unmappedTargetPolicy = ReportingPolicy.IGNORE )
public interface BookMapper {
    BookMapper INSTANCE = Mappers.getMapper(BookMapper.class);

    Book map(BookWriteModel bookWriteModel, @Context User user);

    @ObjectFactory
    default Page create(@Context User user) {
        Page page = new Page();
        if (user != null) {
            page.userId = user.userId;
        }
        return page;
    }
}

生成的代码：

@Component
public class BookMapperImpl implements BookMapper {
    @Override
    public Book map(BookWriteModel bookWriteModel, User user) {
        if ( bookWriteModel == null ) {
            return null;
        }
        Book book = new Book();
        book.pages = pageWriteModelListToPageList( bookWriteModel.pages, user );
        return book;
    }

    protected Page pageWriteModelToPage(PageWriteModel pageWriteModel, User user) {
        if ( pageWriteModel == null ) {
            return null;
        }
        Page page = create( user );
        page.pageNumber = pageWriteModel.pageNumber;
        return page;
    }

    protected List<Page> pageWriteModelListToPageList(List<PageWriteModel> list, User user) {
        if ( list == null ) {
            return null;
        }
        List<Page> list1 = new ArrayList<Page>( list.size() );
        for ( PageWriteModel pageWriteModel : list ) {
            list1.add( pageWriteModelToPage( pageWriteModel, user ) );
        }
        return list1;
    }
}

解决方案3:使用 @上下文 来收集 @ObjectFactory 和附加映射方法

@Mapper( componentModel = "spring", unmappedTargetPolicy = ReportingPolicy.IGNORE)
public interface BookMapper {
    BookMapper INSTANCE = Mappers.getMapper(BookMapper.class);

    Book map(BookWriteModel bookWriteModel, @Context User user);
    
    Page map(User user);

    @ObjectFactory
    default Page create(@Context User user) {
        Page page = map(user);
        return page == null ? new Page() : page;
    }
}

生成的代码：

@Component
public class BookMapperImpl implements BookMapper {
    @Override
    public Book map(BookWriteModel bookWriteModel, User user) {
        if ( bookWriteModel == null ) {
            return null;
        }
        Book book = new Book();
        book.pages = pageWriteModelListToPageList( bookWriteModel.pages, user );
        return book;
    }

    @Override
    public Page map(User user) {
        if ( user == null ) {
            return null;
        }
        Page page = new Page();
        page.userId = user.userId;
        return page;
    }

    protected Page pageWriteModelToPage(PageWriteModel pageWriteModel, User user) {
        if ( pageWriteModel == null ) {
            return null;
        }
        Page page = create( user );
        page.pageNumber = pageWriteModel.pageNumber;
        return page;
    }

    protected List<Page> pageWriteModelListToPageList(List<PageWriteModel> list, User user) {
        if ( list == null ) {
            return null;
        }
        List<Page> list1 = new ArrayList<Page>( list.size() );
        for ( PageWriteModel pageWriteModel : list ) {
            list1.add( pageWriteModelToPage( pageWriteModel, user ) );
        }
        return list1;
    }
}

解决方案4: @上下文 方法作为映射方法的代理

@Mapper( componentModel = "spring", unmappedTargetPolicy = ReportingPolicy.IGNORE)
public interface BookMapper {
    BookMapper INSTANCE = Mappers.getMapper(BookMapper.class);

    Book map(BookWriteModel bookWriteModel, @Context User user);

    Page map(PageWriteModel pageWriteModel, User user);

    default Page mapContext(PageWriteModel pageWriteModel, @Context User user) {
        return map(pageWriteModel, user);
    }
}

生成的代码：

@Component
public class BookMapperImpl implements BookMapper {

    @Override
    public Book map(BookWriteModel bookWriteModel, User user) {
        if ( bookWriteModel == null ) {
            return null;
        }

        Book book = new Book();

        book.pages = pageWriteModelListToPageList( bookWriteModel.pages, user );

        return book;
    }

    @Override
    public Page map(PageWriteModel pageWriteModel, User user) {
        if ( pageWriteModel == null && user == null ) {
            return null;
        }

        Page page = new Page();

        if ( pageWriteModel != null ) {
            page.pageNumber = pageWriteModel.pageNumber;
        }
        if ( user != null ) {
            page.userId = user.userId;
        }
        return page;
    }

    protected List<Page> pageWriteModelListToPageList(List<PageWriteModel> list, User user) {
        if ( list == null ) {
            return null;
        }
        List<Page> list1 = new ArrayList<Page>( list.size() );
        for ( PageWriteModel pageWriteModel : list ) {
            list1.add( mapContext( pageWriteModel, user ) );
        }
        return list1;
    }
}

我认为，解决方案4是明确和更好的。

票数 0

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/72548938

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