DTO到实体和实体到DTO

Question

我们将使用DTO向表示层发送数据和从表示层发送数据.我们有以下层次:

• 正面
• AppService服务
• 域

我们使用Dozer帮助我们将实体转换为dto.但我现在有2个问题:

1. 从实体到dto我们可以使用推土机,但从dto到实体我们可以使用推土机吗？如果是,怎么样？
2. 我应该创建实体吗？在门面或DTOAssembler？

例如,我必须注册一本书.实体看起来像:

Book{
   public Book(BookNumber number,String name){
      //make sure every book has a business number,
      //and the number can't change once the book is created.
      this.bookNumber = number;
      ..
   }
}

我们有一个DTOAssembler:

BookDTOAssembler{

  BookDTO toDAO(bookEntity){
  ...
  }
  BookEntiy fromDTO(book DTO,BookRepository bookRepository){
    //1.Where should i create book entity? 
    //2.Is there any effective way to convert dto to entity in java world?
  }
}

选项1

the BookManagedFacade has a registerBook function:
public registerBook(bookDTO){
   Book book = BookDTOAssembler.fromDTO(book DTO);
}

//Create book in BookDTOAssembler.fromDTO 
public static BookEntiy fromDTO(BookDTO bookDTO,BookRepository bookRepository){
    //book is never registered 
    if (0==bookDTO.getBookID()){
       Book book = new Book(bookRepository.generateNextBookNumber(),bookDTO.getName());
    }else{
       //book is been registed so we get it from Repository
       book = bookRepository.findById(bookDTO.getBookID()); 
    }
    book.setAuthor(bookDTO.getAuthor);
    ...
    return book;
}

选项2

the BookManagedFacade has a registerBook function:
public registerBook(bookDTO){
   Book book = new Book(bookRepository.generateNextBookNumber(),bookDTO.getName());
   book = BookDTOAssembler.fromDTO(book DTO,book);
}

//add another function in BookDTOAssembler.fromDTO 
public static BookEntiy fromDTO(BookDTO bookDTO,Book book){
    book.setAuthor(bookDTO.getAuthor);
    ...
    return book;
}

一个更好吗？或者它可以以更好的方式实施..？

Answer 1

通常,您不会将对象(域实体的DTO表示)传输回服务器.因为如果你这样做,你就会打破封装,因为任何人都可以将更改应用到DTO,然后再发回信息.

相反,您应该创建一个用于修改对象的服务接口,因为它允许服务器将更改应用于它的模型.

因此,该服务实际上分为两部分:

1. 查询部分,用于获取所有实体的DTO表示
2. 命令部分,用于将更改应用于实体