带Querydsl的弹簧:java.lang.ClassCastException类

我需要nBuildId来查找building表中的building name。那么我如何迭代这个呢 List<Tuple>

我试过了

 public  List<Tuple> loadUnclamiedRoomGrid(Integer nBuildId, String sFloor) {

        QRoom room = QRoom.room;        
        QRoomDepartmentMapping roomDepartmentMapping = QRoomDepartmentMapping.roomDepartmentMapping;

        JPAQuery<Tuple> query = new JPAQuery<Tuple>(em);

        query
             .from(room) 
             .where(room.nRoomId.notIn
                         (JPAExpressions.select(roomDepartmentMapping.nRoomId)
                               .from(roomDepartmentMapping)
                         )
               );

        if (nBuildId != null && nBuildId !=0) {
            query.where(room.nBuildId.eq(nBuildId));
        }

        if(sFloor != null) {
            query.where(room.sFloor.eq(sFloor));
        }   

        List<Tuple> queryResult = query.fetch();

        for(Tuple row : queryResult) {

            System.out.println("Build Id " +row.get(room.nBuildId));
        }

    return queryResult; 

    }

message: "com.spacestudy.model.Room cannot be cast to com.querydsl.core.Tuple",
Exception: "java.lang.ClassCastException"