我是 Querydsl 的新手,我正在寻找一种基于过滤器附加/构建谓词的方法。您可以在示例中看到,如果过滤器中的某个字段没有值,则不应将其放入谓词中。
如果这样的事情不可能,那么最好的方法是什么?
例如过滤器(GetPaintingRequest)包含这些字段(过滤器中还有更多,但不重要):
public class GetPaintingsRequest {
private String author;
private Integer style;
private String paintingName;
//.....getters and setters
}
所以在服务类中我想像这样过滤绘画
public List<Painting> getFilteredPaintings(GetPaintingsRequest request) {
QPainting painting = QPainting.painting;
//predicate for all paintings that are not deleted and not sold
Predicate query = painting.deleted.isFalse().and(painting.isSold.isFalse());
if (!request.getAuthor().equals("")) {
//append to existing predicate name of the author
query.and.painting.autor.eq(request.getAuthor()); //obviously not working - just as an example what I want
}
if (!request.getPaintingName().equals("")) {
//append to existing predicate painting name
query.and.painting.paintingName.eq(request.getPaintingName()); //obviously not working - just as an example what I want
}
var paintingList = paintingRepository.findAll(query);
}
我找到了解决办法!
QPainting painting = QPainting.painting;
BooleanBuilder booleanBuilder = new BooleanBuilder();
booleanBuilder.and(painting.deleted.isFalse().and(painting.isSold.isFalse()));
if (!request.getAuthor().equals("")) {
booleanBuilder.and(painting.author.eq(request.getAuthor()));
}
if (!request.getPaintingName().equals("")) {
booleanBuilder.and(painting.paintingName.eq(request.getPaintingName()));
}
Predicate predicate = booleanBuilder;
var paintingList = paintingRepository.findAll(predicate);