java - 发现某些内容时不打印 "not found"

Question

我正在尝试做这个项目，但由于某种原因，我遇到了一个我一生都无法解决的问题。

public static void printlist(String n){
    for(int i=0; i<  roomlist.size(); i++){
        if(roomlist.get(i).name.equals(n)){
            System.out.println("Room Name: " + roomlist.get(i).name + " state:     " + roomlist.get(i).state);
            System.out.println("Description: " + roomlist.get(i).desc);
            System.out.println("Creatures in Room: " + roomlist.get(i).Fred());
            if(roomlist.get(i).north != null){
                System.out.println("North Neighbor: " + roomlist.get(i).north.name);
            }
            if (roomlist.get(i).south !=null){
                System.out.println("South Neighbor: " + roomlist.get(i).south.name);
            }
            if (roomlist.get(i).east !=null){
                System.out.println("East Neighbor: " + roomlist.get(i).east.name);
            }
            if (roomlist.get(i).west !=null){
                System.out.println("West Neighbor: " + roomlist.get(i).west.name);
            }
        }

    }
    System.out.println("Room " + n + " does not exist!");
}

现在，即使它在 ArrayList 中找到 Room 对象，它仍然会打印“Room "+ n + "does not exit!”我需要它仅在 ArrayList 中找不到房间时才打印该信息

Answer 1

发生这种情况的原因是因为未找到消息是您的方法的最后一条语句。相反，您应该在找到元素并打印所需消息后立即从该方法返回。

例如，假设每个房间都有一个唯一的名称:

...
if (roomlist.get(i).name.equals(n)) {
    ...
    if (roomlist.get(i).west != null) {
       System.out.println("West Neighbor: " + roomlist.get(i).west.name);
    }
    return;
}
...