Spring Boot + Spring Data Jpa

BookQueryService.java

public interface BookQueryService {
    Page<Book> findBookNoCriteria(Integer page,Integer size);
    Page<Book> findBookCriteria(Integer page,Integer size,BookQuery bookQuery);
}

BookQueryServiceImpl.java

@Service
public class BookQueryServiceImpl implements BookQueryService {
    @Resource
    BookRepository bookRepository;
    @Override
    public Page<Book> findBookNoCriteria(Integer page,Integer size) {
        Pageable pageable = new PageRequest(page, size, Sort.Direction.ASC, "id");
        return bookRepository.findAll(pageable);
    }
 
    @Override
    public Page<Book> findBookCriteria(Integer page, Integer size, final BookQuery bookQuery) {
        Pageable pageable = new PageRequest(page, size, Sort.Direction.ASC, "id");
        Page<Book> bookPage = bookRepository.findAll(new Specification<Book>(){
            @Override
            public Predicate toPredicate(Root<Book> root, CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
                List<Predicate> list = new ArrayList<Predicate>();
                if(null!=bookQuery.getName()&&!"".equals(bookQuery.getName())){
                    list.add(criteriaBuilder.equal(root.get("name").as(String.class), bookQuery.getName()));
                }
                if(null!=bookQuery.getIsbn()&&!"".equals(bookQuery.getIsbn())){
                    list.add(criteriaBuilder.equal(root.get("isbn").as(String.class), bookQuery.getIsbn()));
                }
                if(null!=bookQuery.getAuthor()&&!"".equals(bookQuery.getAuthor())){
                    list.add(criteriaBuilder.equal(root.get("author").as(String.class), bookQuery.getAuthor()));
                }
                Predicate[] p = new Predicate[list.size()];
                return criteriaBuilder.and(list.toArray(p));
            }
        },pageable);
        return bookPage;
    }
  
    /*
    @Override
    public Page<Book> findBookCriteria(Integer page, Integer size, final BookQuery bookQuery) {
        Pageable pageable = new PageRequest(page, size, Sort.Direction.ASC, "id");
        Page<Book> bookPage = bookRepository.findAll(new Specification<Book>(){
            @Override
            public Predicate toPredicate(Root<Book> root, CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
                Predicate p1 = criteriaBuilder.equal(root.get("name").as(String.class), bookQuery.getName());
                Predicate p2 = criteriaBuilder.equal(root.get("isbn").as(String.class), bookQuery.getIsbn());
                Predicate p3 = criteriaBuilder.equal(root.get("author").as(String.class), bookQuery.getAuthor());
                query.where(criteriaBuilder.and(p1,p2,p3));
                return query.getRestriction();
            }
        },pageable);
        return bookPage;
    }
    */
}

BookRepository.java

@Repository("bookRepository")
public interface BookRepository extends JpaRepository<Book,Long>
        ,JpaSpecificationExecutor<Book> {
}