java实现双向链表

    双向链表是一个基本的数据结构，在java中LinkedList已经实现了这种结构，不过作为开发者，也要拥有自己显示这种结构的能力。话不多说，上代码：

    首先是链表的节点类：

/** * 链表节点 * @author Administrator * * @param <T> */public class ChainNode<T> {private T data;//对象编号private int dataNo;public ChainNode<T> nextChainNode;public ChainNode<T> preChainNode;public ChainNode(T data, ChainNode<T> nextChainNode,ChainNode<T> preChainNode) {this.data = data;this.nextChainNode = nextChainNode;this.preChainNode = preChainNode;}public ChainNode(T data) {this.data = data;}public int getDataNo() {return dataNo;}public void setDataNo(int dataNo) {this.dataNo = dataNo;}public void setData(T data) {this.data = data;}public T getData() {return data;}}

然后是链表：

<pre name="code" class="java">/** * 链表实现类 * @author Administrator * * @param <T> */public class Chain<T> {//头节点private ChainNode<T> headNode;//末尾节点指针private ChainNode<T> lastNode;private int size;//创建链表就创建头节点public Chain() {this.headNode = new ChainNode<T>(null);this.lastNode = headNode;}//增加一个节点public void addNode(T data) {ChainNode<T> node = new ChainNode<T>(data);if(lastNode != null){lastNode.nextChainNode = node;node.preChainNode = node;node.setDataNo(size);lastNode = node;size++;}}//删除指定索引的节点public void deleteNode(int dataNo) throws Exception {if(getSize() == 0){throw new Exception("chain is empty");}for (ChainNode<T> node = headNode.nextChainNode;node != null;node = node.nextChainNode) {if(node.getDataNo() == dataNo){node.preChainNode.nextChainNode = node.nextChainNode;if(node.nextChainNode != null){node.nextChainNode.preChainNode = node.preChainNode;}node.nextChainNode = null;node.preChainNode = null;size--;//重新设置节点的编号for (ChainNode<T> chainNode = node.nextChainNode;chainNode != null;chainNode = chainNode.nextChainNode) {chainNode.setDataNo(chainNode.getDataNo()-1);}return;}}throw new Exception("the corresponding data that can not be found");}//获取指定索引的节点public T  get(int dataNo) throws Exception {if(getSize() == 0){throw new Exception("chain is empty");}for (ChainNode<T> node = headNode.nextChainNode;node != null;node = node.nextChainNode) {if(node.getDataNo() == dataNo){return  node.getData();}}throw new Exception("the corresponding data that can not be found");}//修改对应索引的节点public void set(int dataNo,T data) throws Exception {if(getSize() == 0){throw new Exception("chain is empty");}for (ChainNode<T> node = headNode.nextChainNode;node != null;node = node.nextChainNode) {if(node.getDataNo() == dataNo){node.setData(data);return;}}throw new Exception("the data that is to be modified can not be found");}//是否包含对应数据的节点public boolean isContains(T data) throws Exception {if(getSize() == 0){throw new Exception("chain is empty");}for (ChainNode<T> chainNode = headNode.nextChainNode;chainNode != null;chainNode = chainNode.nextChainNode) {if(chainNode.getData() == data){return true;}}return false;}//获取节点数量（不含头节点）public int getSize() {return size;}}

测试一下：

public class ChainTest {public static void main(String[] args) throws Exception{String oneString = "one";String twoString = "two";String threeString = "three";String fourString = "four";Chain<String> chain = new Chain<String>();chain.addNode(oneString);chain.addNode(twoString);chain.addNode(threeString);chain.addNode(fourString);for (int i = 0; i < chain.getSize(); i++) {String string2 = chain.get(i);System.out.println(string2);}try {String string = chain.get(2);System.out.println("the data of the second node is"+string);System.out.println(chain.isContains(fourString));chain.set(1, "haha");System.out.println("modify chain");for (int i = 0; i < chain.getSize(); i++) {String string2 = chain.get(i);System.out.println(string2);}chain.deleteNode(3);System.out.println("delete one node");for (int i = 0; i < chain.getSize(); i++) {String string2 = chain.get(i);System.out.println(string2);}} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}

结果：

one
two
three
four
the data of the second node isthree
true
modify chain
one
haha
three
four
delete one node
one
haha
three