带有Querydsl的Spring：java.lang.ClassCastException

Question

我正在尝试迭代Querydsl的查询结果。为了迭代查询结果，我在每个循环中使用。但是我遇到了类强制转换异常。

我想要nBuildId来查找建筑物表中的建筑物名称。因此，我如何迭代此List<Tuple>以获得专栏。

我尝试过这样

 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; 

    }

错误

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

Answer 1

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

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

        JPAQuery<Room> query = new JPAQuery<Room>(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<Room> queryResult = query.fetch();

        for(Room row : queryResult) {

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

    return queryResult; 

    }