自己写的一个linkedList

public class linkedList<T> { private Node<T> node; private int listSize; //构造方法 public linkedList(){ node = new Node<T>(); listSize = 0; } //在索引index处添加元素 public void add(int index, T element) { if(index <0 || index >listSize){ return; } Node<T> preNode = node; for(int i=0;i<index;i++) preNode = preNode.next; Node<T> newNode = new Node<T>(element); if(preNode.next!=null){ preNode.next.prev = newNode; newNode.next = preNode.next; } newNode.prev = preNode; preNode.next = newNode; listSize++; } //在尾部添加元素并返回true public boolean add(T element) { this.add(listSize, element); return true; } //返回第一个element元素的索引 public int indexOf(T element) { Node<T> curNode = node; for(int i=0;i<=listSize-1;i++){ curNode = curNode.next; if(curNode.equals(element)) return i; } return -1; } //返回最后一个element元素的索引 public int lastIndexOf(T element) { int index =-1; Node<T> curNode = node; for(int i=0;i<=listSize-1;i++){ curNode = curNode.next; if(curNode.equals(element)) index = i; } return index; } //得到索引index处的节点 public Node<T> getNode(int index){ Node<T> curNode = node; for(int i=0;i<=index;i++){ curNode = curNode.next; } return curNode; } //得到索引index处的元素 public T get(int index) { if(index <0 || index >=listSize){ return null; } return this.getNode(index).value; } //为索引index处的元素赋值 public T set(int index, T element) { if(index <0 || index >=listSize){ return null; } T previousValue = this.get(index); Node<T> curNode = this.getNode(index); curNode.value = element; return previousValue; } //删除索引index处的元素 public T remove(int index) { if(index <0 || index >=listSize){ return null; } Node<T> curNode = this.getNode(index); curNode.prev.next = curNode.next; if(curNode.next!=null) curNode.next.prev = curNode.prev; listSize--; return curNode.value; } //删除列表中的element元素 public boolean remove(T element) { int index = this.indexOf(element); if(index != -1){ this.remove(index); return true; } return false; } //返回列表的长度 public int size() { return listSize; } //判断列表是否为空 public boolean isEmpty() { return listSize==0; } //清空列表 public void clear() { node = null; listSize = 0; } //判断列表中是否存在元素element public boolean contains(T element) { return !(this.indexOf(element)==-1); } //节点 @SuppressWarnings("hiding") private class Node<T>{ public T value; public Node<T> prev; public Node<T> next; public Node(){}; public Node(T t){ this.value = t; } } //测试 public static void main(String[] args) { linkedList<String> l = new linkedList<String>(); l.add("taitaitai"); l.add("hehehe"); l.add(1,"hahaha"); System.out.println("size=:"+l.size()); for(int i=0;i<l.size();i++){ System.out.print(l.get(i)+" , "); } System.out.println(); l.remove(2); System.out.println(l.get(2)); } }