求解答java数据结构解答

public class Node {
public int data; public Node next;
public Node0 { next = null; }
带附设头结点的单链表类List定义如下：
public class List {
private Node head;
public ListO { head = new Node; }
}
编写List类中的getLengthO方法，返回单链表的长度。

参考如下：

public class List {
    private Node head;
    public List() { head = new Node; }

    public int getLength() {
        int length = 0;
        Node temp = head;
        while (null != temp) {
            length++;
            temp = temp.next;
        }
        return length;
    }
}