MapStruct有多种工具可用于这种情况：

1. Qualifier

我们可以提供Entity字段类型之间的自定义Map逻辑：List<Book>和DTO字段类型Book：

interface BookingMapping {
    @Mapping(target = "newestBook", source = "listBook", qualifiedBy=NewestBookQualifier.class)
    //.. other fields
    AuthorNewestBookDto toDtoQualifiedBy(Author entity);
}
...
public class BookingMappingUtil { 
    @NewestBookQualifier
    BookDto toNewestBook(List<Book> listBook) {
        return listBook.stream()
             .max(Comparator.comparing(Book::getPublishedDateTime))
             .orElse(null)
}
...
@Qualifier
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.SOURCE)
public @interface NewestBookQualifier{
}

Iterable to non-iterable example（官方MapStruct-Example项目）。

2. @Named

在这种情况下，我们不需要创建新的注解。命名注解文档

@Mapping(target = "newestBook", source = "listBook", qualifiedByName="toNewestBook" )
//.. other fields
AuthorNewestBookDto toDtoQualifiedByName(Author entity);

@Named("toNewestBook")
default BookDto toNewestBook(List<Book> listBook) {
    return listBook.stream()
             .max(Comparator.comparing(Book::getPublishedDateTime))
             .orElse(null)
}

3. @Mapping(.. expression=".." ..)

我们可以将业务逻辑存储为String。这种方法可能不是可读的，但很容易实现。表达式文档

@Mapping(target = "newestBook", 
          source = "listBook", 
          expression = "java( listBook.stream().max(java.util.Comparator.comparing(Book::getPublishedDateTime)).orElse(null) )" )
//.. other fields
AuthorNewestBookDto toDtoQualifiedByName(Author entity);