1. 代码
   1. 节点：单链表节点LinkNode 
   2. 链表：单链表 -->额外方法：getIterator()
      1. public class IteratorLinkList extends List {    static LinkNode first = null;        public LinkNode getFirst(){        return first;    }        public  void setFirst(LinkNode first) {        IteratorLinkList.first = first;    }    public boolean isEmpty() {        return first==null;    }    public void  insertFirst(LinkNode o1) {
                  // 头插法        if(isEmpty()) {            first= o1;            return;        }        o1.next = first;        first = o1;    }         // 在指定节点后插入新节点    public static void insertAfter(LinkNode o1, LinkNode o2) {        LinkNode current = first;        LinkNode previous = null;        while(current!=null){            if(current.iData == o1.iData && current.dData == o1.dData){                o2.next = current;                previous.next = o2;                return;            }            previous = current;            current = current.next;        }        throw new RuntimeException("没有找到该节点");    }    public   LinkNode  deleteFirst() {
                  // 删除头节点        if(isEmpty()) {            throw new RuntimeException("链表为空无法进行删除操作");        }        LinkNode temp = first;        first= first.next;         return temp;    }    // 显示链表    public void displayList() {        LinkNode current = first;        System.out.println("Display from Front--->End");        while(current!=null){            System.out.print(current.iData + "  "+ current.dData+"  ");            System.out.println();            current= current.next;        }    }    // 找到指定节点    public static LinkNode findNode(LinkNode o) {        LinkNode current = first;        while(current!=null){            if(current.iData == o.iData && current.dData == o.dData){                return current;            }            current = current.next;        }        throw new RuntimeException("没有找到该节点");    }    // 删除指定节点    public void deleteNode(LinkNode o) {        if(isEmpty()) {            throw new RuntimeException("链表为空无法进行删除操作");        }        LinkNode current = first;        LinkNode previous = null;        while(current!=null){            if(current.iData == o.iData && current.dData == o.dData){                previous.next = current.next;                return;            }            previous = current;            current = current.next;        }        throw new RuntimeException("没有找到该节点");    }       public ListIterator getIterator()  // return iterator          {          return new ListIterator(this);  // initialized with          }  }
   3. 迭代器：
      • public class ListIterator {    //current link    private LinkNode current;    //previous link    private LinkNode previous;    //the  target link list    private IteratorLinkList ourList;            public ListIterator(IteratorLinkList ourList) {        super();        this.ourList = ourList;    }    //reset the iterator :let it start at first    public void reset(){        current = ourList.getFirst();        previous = null;    }    public boolean atEnd(){
                 //whether at the end of target linklist        return current.next==null;    }    public void nextLink() {        // step to next link        previous = current;        current = current.next;    }    public LinkNode getCurrent()  {     // get current link        return current;    }     public void insertAfter(LinkNode dd){
                 //insert after current link         if( ourList.isEmpty()) {             ourList.setFirst(dd);             reset();         }          dd.next = current.next;         current.next = dd;         nextLink();     }     public void insertBefore(LinkNode dd){
                 //insert before current link         if( ourList.isEmpty()) {
                 // the list is empty             ourList.setFirst(dd);             reset();         } if(previous==null){
                 // there is only one item in the list             ourList.setFirst(dd);             dd.next = current;             reset();         }else{
                 // there is more than one item in the list            dd.next = current;            previous.next = dd;            current = dd;         }     }     public LinkNode deleteCurrent() {   // delete item at current         LinkNode temp = current;         if( ourList.isEmpty()) {
                 // the list is empty             throw new RuntimeException("The List is empty ,could not be deleted any more");         } if(previous==null){
                 // there is only one item in the list             ourList.setFirst(null);              reset();         }else{
                 // there is more than one item in the list            previous.next = current.next;            if( atEnd() )                reset();             else                current = current.next;         }         return temp;     }}

         

        迭代器插入节点：在当前节点之后插入新的节点

      • 基于单链表的迭代器:

      • ListIterator

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        方法总结:

         

      • 当前链表没有任何节点

         

         

        当前链表节点数>1