toString方法用Java调用 [英] toString Method Call in Java

问题描述

可能重复：

为什么在打印对象时调用toString（）方法？

我在下面有这段代码。我使用Room Class 中的 toString方法了解除输出之外的所有其他内容。在 HotelMain 类中，我刚刚调用了酒店类中的 displayRooms Method 。但是，当我运行程序时，toString输出显示在控制台中。

I have this piece of code below. I understand everything else except the output using the toString method in the Room Class . In the HotelMain Class, I just called the displayRooms Method that was in the Hotel Class. But, when I ran the program, the toString output was shown in the console.

如果我是对的，则toString（）是对象中值的文本表示。但是，我不确定我在哪里调用toString方法。

If I'm right toString() is the textual representation of the value in the object. But, I'm not sure where I called the toString method.

有人可以解决我的困境吗？谢谢。

Can someone solve my dilemma? Thank You.

酒店等级

public class Hotel {

private String hotelName;
private Room[] rooms;

public Hotel(String hotelName, int numberOfRooms) {
    this.hotelName = hotelName;
    this.rooms = new Room[numberOfRooms];
}

public void addRooms(Room room) {

    int position = -1;

    for (int i = 0; i < this.rooms.length; i++) {
        Room tempRoom = rooms[i];

        if (tempRoom == null) {
            position = i;
            break;
        }
    }

    if (position != -1) {
        rooms[position] = room;
        System.out.println("New room added at postion " + position);

    } else {
        System.out.println("Addition of room failed.");
    }
}

public void displayRooms() {

    System.out.println("The Hotel: " + this.hotelName + " has the following rooms.");

    for (int i = 0; i < this.rooms.length; i++) {
        Room tempRoom = rooms[i];
        if (tempRoom != null) {
            System.out.println(tempRoom);
        }
    }

}

房间等级

public class Room {

private int roomNumber;
private int numberOfBeds;
private boolean smokingOrNonSmoking;

public Room() {

}

public Room(int roomNumber, int numberOfBeds, boolean smokingOrNonSmoking) {
    this.roomNumber = roomNumber;
    this.numberOfBeds = numberOfBeds;
    this.smokingOrNonSmoking = smokingOrNonSmoking;
}

@Override
public String toString() {
    return "Room [roomNumber=" + roomNumber + ", numberOfBeds="
            + numberOfBeds + ", smokingOrNonSmoking=" + smokingOrNonSmoking
            + "]";
}

}

Hotel Main

public class HotelMain {

public static void main(String[] args) {

Hotel hotel = new Hotel("MahaRani Chain of Hotels", 10);
Room room1 = new Room(4, 2, true);
Room room2 = new Room(2, 1, false);
Room room3 = new Room(6, 3, true);
Room room4 = new Room(6, 4, false);

hotel.addRooms(room1);
hotel.addRooms(room3);
hotel.addRooms(room4);
hotel.addRooms(room2);

hotel.displayRooms();

}

}

控制台

推荐答案

Room tempRoom = rooms[i];
if (tempRoom != null) {
    System.out.println(tempRoom);
}

您的 displayRooms（）中有以上代码方法。它打印 tempRoom ，这是 Room 的引用，因此它调用 toString（） 在 Room 类中重写的方法。

You have the above code in your displayRooms() method. It prints tempRoom, which is a reference of Room, and hence it calls toString() method overridden in the Room class.

这篇关于toString方法用Java调用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！