如何替换文本文件中的对象并将其保存到文本文件？？？
首先我要添加单独的房间。

for (int i = 0; i < lines.size() - 1; i++){

    String[] words = lines.get(i).split(" ");
    var room = new Room();
    room.roomNum = Integer.parseInt(words[0]);
    room.roomType = (words[1]);
    room.roomPrice = Double.parseDouble(words[2]);
    room.hasBalcony = Boolean.parseBoolean(words[3]);
    room.hasLounge = Boolean.parseBoolean(words[4]);
    room.eMail = (words[5]);
    rooms.add(room);                   
}

然后我在文本文件中搜索一个特定的房间，并将selectedroom.email替换为reservemail。

System.out.println("\n-- ROOM RESERVATION --");
System.out.println("Please enter the room number you wish to reserve"); 

Room selectedRoom = null;
var searchRoomNum = input.nextInt();

for(int i = 0; i < rooms.size(); i++){                 
    if(rooms.get(i).roomNum == searchRoomNum){                    
        selectedRoom = rooms.get(i);     
    }
}

if(selectedRoom.eMail.contentEquals("free")) {  
    System.out.println("Please Enter your email");
        var reserveEmail = input.next();
            selectedRoom.eMail = reserveEmail;
            System.out.println("Thanks, this room has been reserved");
            return;
}

我需要知道如何将此更改保存到它来自的文本文件中，而不覆盖整个文件。