Question

我有一个Node Class和TestMain Class，我用它来创建和测试链接列表。我已经重写了Node类中的toString方法来打印Node（值和next）。但它以递归方式打印List。我想只打印我指定的节点。有人可以告诉我

为什么我的toString以递归方式打印整个列表？
需要更改什么才能在main（）



public class Node {
    private int value;
    private Node next;

    Node(int value){
        this.value=value; 
    }

    public int getValue() {
        return value;
    }

    public void setValue(int value) {
        this.value = value;
    }

    public Node getNext() {
        return next;
    }

    public void setNext(Node next) {
        this.next = next;
    }

    public String toString(){
        return "value = " +  this.value + ", next = " + getNext();
    }
}


public class TestMain {

    public static void main(String[] args) {
        System.out.println("Begin TestMain \n");

        Node head = new Node(10);
        Node n1 = new Node(11);
        Node n2 = new Node(12);
        Node n3 = new Node(13);

        head.setNext(n1);
        n1.setNext(n2);
        n2.setNext(n3);

        System.out.println("Head : " + head);
        System.out.println("n1 : " + n1);
        System.out.println("n2 : " + n2);
        System.out.println("n3 : " + n3);

        System.out.println("\nEnd TestMain");

    }

}


//>>>>>> output <<<<<<<<<
Begin TestMain 

Head : value = 10, next = value = 11, next = value = 12, next = value = 13, next = null
n1 : value = 11, next = value = 12, next = value = 13, next = null
n2 : value = 12, next = value = 13, next = null
n3 : value = 13, next = null

End TestMain

//>>>>> Expected Output <<<<<<<<
Begin TestMain 

Head : value = 10, next = addressOf-n1
n1 : value = 11, next = addressOf-n2
n2 : value = 12, next = addressOf-n3
n3 : value = 13, next = null

End TestMain

public class Node { private int value; private Node next; Node(int value){ this.value=value; } public int getValue() { return value; } public void setValue(int value) { this.value = value; } public Node getNext() { return next; } public void setNext(Node next) { this.next = next; } public String toString(){ return "value = " + this.value + ", next = " + getNext(); } } public class TestMain { public static void main(String[] args) { System.out.println("Begin TestMain \n"); Node head = new Node(10); Node n1 = new Node(11); Node n2 = new Node(12); Node n3 = new Node(13); head.setNext(n1); n1.setNext(n2); n2.setNext(n3); System.out.println("Head : " + head); System.out.println("n1 : " + n1); System.out.println("n2 : " + n2); System.out.println("n3 : " + n3); System.out.println("\nEnd TestMain"); } } //>>>>>> output <<<<<<<<< Begin TestMain Head : value = 10, next = value = 11, next = value = 12, next = value = 13, next = null n1 : value = 11, next = value = 12, next = value = 13, next = null n2 : value = 12, next = value = 13, next = null n3 : value = 13, next = null End TestMain //>>>>> Expected Output <<<<<<<< Begin TestMain Head : value = 10, next = addressOf-n1 n1 : value = 11, next = addressOf-n2 n2 : value = 12, next = addressOf-n3 n3 : value = 13, next = null End TestMain

Answer 1

您正尝试在toString（）方法中打印getNext()。

return "value = " +  this.value + ", next = " + getNext();

这意味着下一个Node也会调用它的toString()方法。然后该节点将调用ITS下一个节点的toString，依此类推。您需要删除该部分以避免打印出整个列表。

    return "value = " +  this.value;

然后，如果您需要打印下一个节点，则必须从方法外部执行此操作。不应该是toString（）负责打印出下一个节点值。

Answer 2

写作时

SomeObject object = new SomeObject();
System.out.println(object);

它隐式调用SomeObject类toString（）方法，该方法来自Object类toString（）。它与

相同

SomeObject object = new SomeObject();
System.out.println(object.toString());

默认情况下，Object类具有toString（）方法，该方法返回：

public String toString() { {
{1}} {
{1}}

但是你已经覆盖了toString（）方法，所以现在它不能返回“地址”，因为你已经改变了方法！您可以尝试以下代码：


        return getClass().getName() + "@" + Integer.toHexString(hashCode());

这不是编程的艺术，但我希望它能按你的意愿运作。

覆盖toString Java以打印链接列表节点

2 个答案: