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RecordMapper
Applies to ✅ Open Source Edition ✅ Express Edition ✅ Professional Edition ✅ Enterprise Edition
In a more functional operating mode, you might want to write callbacks that map records from your select statement results in order to do some processing. This is a common data access pattern in Spring's JdbcTemplate, and it is also available in jOOQ. With jOOQ, you can implement your own org.jooq.RecordMapper classes and plug them into jOOQ's org.jooq.ResultQuery:
// Write callbacks to receive records from select statements
List<Integer> ids =
create.selectFrom(BOOK)
.orderBy(BOOK.ID)
.fetch()
.map(BookRecord::getId);
// Or more concisely, as fetch().map(mapper) can be written as fetch(mapper):
create.selectFrom(BOOK)
.orderBy(BOOK.ID)
.fetch(BookRecord::getId);
// Or using a lambda expression:
create.selectFrom(BOOK)
.orderBy(BOOK.ID)
.fetch(book -> book.getId());
// Of course, the lambda could be expanded into the following anonymous RecordMapper:
create.selectFrom(BOOK)
.orderBy(BOOK.ID)
.fetch(new RecordMapper<BookRecord, Integer>() {
@Override
public Integer map(BookRecord book) {
return book.getId();
}
});
An alternative utility is offered by org.jooq.Records, which is very useful when working with type safe Record[N] types and constructor references:
// Use Java 16 record types as simple DTOs
record Book (int id, String title) {}
List<Book> books =
create.select(BOOK.ID, BOOK.TITLE)
.from(BOOK)
.orderBy(BOOK.ID)
.fetch(Records.mapping(Book::new));
Your custom RecordMapper types can be used automatically through jOOQ's POJO mapping APIs, by injecting a RecordMapperProvider into your Configuration.
See also the manual's section about the RecordHandler, which provides similar features
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