public class Link {    /**     * 链结点     */    private int iData;    private double dData;    public Link next;        public Link(int iData,double dData)    {        this.dData =http://www.mamicode.com/ dData;        this.iData =http://www.mamicode.com/ iData;    }        //打印节点    public void displayLink()    {        System.out.println("{"+iData+","+dData+"}");    }    }public class LinkList {    //这个类比较简单就有一个指向节点的引用    private Link first;        public LinkList()    {        this.first = null;    }    //判断链表是不是为空    public boolean isEmpty()    {        if(first == null)        {            return true;        }else{            return false;        }    }        //链表的插入头插法(面向对象的思考)    public void insertFirst(Link link)    {        link.next = first;//首先让新生成的节点的next指向first        first = link;    }        //删除的头节点的方法    public Link deleteFirst()    {        //删除节点的原理：让first指向第一个节点的下一个节点        Link temp = first;        first = first.next;        return temp;    }        //打印链表的方法    public void displayList()    {        Link current = first;        while(current != null)        {            current.displayLink();            current = current.next;        }        System.out.println("  ");    }            }