如何将 QueryDSL 中的动态查询转换为 JOOQ？

Question

I use QueryDSL just for dynamic queries in Spring Boot 2+ with Spring Data JPA applications in the following manner:

@Override
public Iterable<Books> search(String bookTitle, String bookAuthor, String bookGenre) {
  BooleanBuilder where = dynamicWhere(bookTitle, bookAuthor, bookGenre);
  return booksRepository.findAll(where, orderByTitle());
}

public BooleanBuilder dynamicWhere(String bookTitle, String bookAuthor, String bookGenre) {
  QBooks qBooks = QBooks.books;
  BooleanBuilder where = new BooleanBuilder();
  if (bookTitle != null) {
    where.and(qBooks.title.equalsIgnoreCase(bookTitle));
  }
  if (bookAuthor!= null) {
    where.and(qBooks.author.eq(bookAuthor));
  }
  if (bookGenre!= null) {
    where.and(qBooks.genre.eq(bookGenre));
  }
  return where;
}

I want to use JOOQ in a similar transparent way, but I do not know how to do it elegantly. I also like that in JOOQ there isn't QBooks-like generated constructs, although I think JOOQ also generates some tables. Anyhow, I am confused and I couldn't find an answer online, so I am asking can it be done and how.

Thanks

Answer 1

jOOQ doesn't have a specific "builder" to construct your predicates. All the "building" API is located directly on the predicate type, ie the Condition

@Override
public Iterable<Books> search(String bookTitle, String bookAuthor, String bookGenre) {
  Condition where = dynamicWhere(bookTitle, bookAuthor, bookGenre);
  return dslContext.selectFrom(BOOKS)
                   .where(where)
                   .orderBy(BOOKS.TITLE)
                   .fetchInto(Books.class);
}

public Condition dynamicWhere(String bookTitle, String bookAuthor, String bookGenre) {
  Condition where = DSL.noCondition();
  if (bookTitle != null) {
    where = where.and(BOOKS.TITLE.equalsIgnoreCase(bookTitle));
  }
  if (bookAuthor!= null) {
    where = where.and(BOOKS.AUTHOR.eq(bookAuthor));
  }
  if (bookGenre!= null) {
    where = where.and(BOOKS.GENRE.eq(bookGenre));
  }
  return where;
}

This is assuming:

1) That you have injected a properly configured DSLContext 2) That you're using jOOQ's code generator

For more information, see also https://www.jooq.org/doc/latest/manual/sql-building/dynamic-sql/