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我正在嘗試使用groupBy子句創建一個JPA Criteria查詢。 就我而言,我的GROUPBY子句是動態的,所以我想利用這個:如何爲JPA標準組By子句創建表達式列表?
CriteriaQuery<T> groupBy(List<Expression<?>> grouping);
而不是通常的:
CriteriaQuery<T> groupBy(Expression<?>... grouping);
的問題是,我掙扎創建這個表達式列表。 這是我現在的代碼:
CriteriaQuery<Tuple> criteria = cb.createTupleQuery();
Root<Foo> foo = criteria.from(Foo.class);
Expression<String> barExp = foo.get("bar");
Expression<String> bazExp = foo.get("baz");
// I'd like to use a Expression List to build a dynamic group by clause with this. But something looks wrong and I don't know where...
List<Expression<String>> groupBy = Arrays.asList(barExp, bazExp);
// Consulta
criteria.multiselect(barExp, bazExp);
criteria.where(where);
// this works:
criteria.groupBy(barExp, bazExp);
// but I'd like to use this, but compiler give me a type error
//criteria.groupBy(groupBy);
TypedQuery<Tuple> query = em.createQuery(criteria);
List<Tuple> result = query.getResultList();
所以就是這樣。 如何爲groupBy動態創建JPA 2條件表達式列表?
在此先感謝!