I have done do get all my data and convert from object to objectDto. But, somehow, I feel like my code is not good yet. Here I need your help, I need any reference/advice to make my code better (in performance). Here is my working code:
@Override
public List<BookDto> findAll() throws Exception {
try {
List<Book> list = bookDao.findAll();
List<BookDto> listDto = new ArrayList<>();
for (Book book : list) {
BookDto bookDto = new BookDto();
Set<AuthorDto> listAuthorDto = new HashSet<AuthorDto>();
Set<Author> dataAuthor = new HashSet<Author>();
book.getAuthor().iterator().forEachRemaining(dataAuthor::add);
BeanUtils.copyProperties(book, bookDto, "author", "category");
bookDto.setCategory(book.getCategory().getCategory());
for (Author author : dataAuthor) {
AuthorDto authorDto = new AuthorDto();
BeanUtils.copyProperties(author, authorDto);
listAuthorDto.add(authorDto);
}
bookDto.setAuthor(listAuthorDto);
listDto.add(bookDto);
}
return listDto;
} catch (Exception e) {
throw new Exception(e);
}
}
and here is the output that I need (already achieved with above code):
[
{
"title": "book1",
"year": "2013",
"author": [
{
"name": "john",
"address": "NY"
},
{
"name": "angel",
"address": "LA"
}
],
"category": "science"
},
{
"title": "book2",
"year": "2014",
"author": [
{
"name": "john",
"address": "NY"
}
],
"category": "science"
},
{
"title": "book3",
"year": "2009",
"author": [
{
"name": "angel",
"address": "LA"
}
],
"category": "comedy"
}
]
Instead of re-inventing the wheel and writing this by yourself you better use an existing library/tool, which is made for this.
I would recommend to use ModelMapper which is a great library for DTO/entity mapping, you will just need one line to convert your entity to DTO, something like:
ModelMapper modelMapper = new ModelMapper();
BookDto bookDTO = modelMapper.map(book, BookDto.class);
You can check the library's Examples page or the Entity To DTO Conversion for a Spring REST API tutorial to get deeper into this library.