java简易双向链表的实现（添加和双向输出操作）

• 节点类
  与单链表的区别主要在于添加节点时，需要指定新添加节点的前驱

class Node{//节点类
private String name;
private Node pervious;
protected Node next;
public Node(){}
public Node(String name){this.setName(name);}
public Node(String name,Node pervious,Node next){
this.name=name;
this.pervious=pervious;
this.next=next;
}
public void setName(String name){this.name=name;}
public void setPervious(Node pervious){this.pervious=pervious;}
public void setNext(Node next){this.next=next;}
public String getName(){return this.name;}
public Node getNext(){return this.next;}
public void addNode(Node newNode){//添加节点
if(this.next==null){
this.next=newNode;
newNode.setPervious(this);//设置新添加节点的前驱节点
}else{
this.next.addNode(newNode);
}
}
public void pPrintNode(){
System.out.println("姓名："+this.getName());
if(this.next!=null){
this.next.pPrintNode();
}
}
public void nPrintNode(){
System.out.println("姓名："+this.getName());
if(this.pervious!=null){
this.pervious.nPrintNode();
}
}
}

链表类，实现双向的遍历输出

class Link{
private static int LENGTH=0;
private Node root;
public Link(){}
public void add(Node newNode){
++LENGTH;
if(this.root==null){
this.root=newNode;
}else{
this.root.addNode(newNode);
}
}
public void pPrint(){
if(this.root==null){//从根节点由前向后输出
System.out.println("空表");
}
System.out.println("从前往后输出：");
this.root.pPrintNode();
}
public Node getLast(){//得到最后一个节点
Node n=new Node();
n=this.root;
for(int i=1;i<LENGTH;++i){//注意下标，不要越界
n=n.next;
}
return n;
}
public void nPrint(Node node){//从指定位置由后向前输出
System.out.println("从后往前输出");
node.nPrintNode();
}
}

测试类

public class Train{
public static void main(String args[]){
Node n1=new Node("张三");
Node n2=new Node("李四");
Node n3=new Node("王五");
Node n4=new Node("赵六");
Node n5=new Node("孙七");
Link l=new Link();
l.add(n1);
l.add(n2);
l.add(n3);
l.add(n4);
l.add(n5);
l.pPrint();
System.out.println();
l.nPrint(l.getLast());
}
}