自己实现LinkedListJAVA103-104

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1、S02E103_01自己实现LinkedList

package com.test.linkedlist;/** * 用来表示一个节点 */public class Node {    Node previous;//该节点的前一个节点    Object obj;//该节点存放的对象    Node next;//该节点的后一个节点    public Node(){    }    public Node(Node previous, Object obj, Node next) {        super();        this.previous = previous;        this.obj = obj;        this.next = next;    }    public Node getPrevious() {        return previous;    }    public void setPrevious(Node previous) {        this.previous = previous;    }    public Object getObj() {        return obj;    }    public void setObj(Object obj) {        this.obj = obj;    }    public Node getNext() {        return next;    }    public void setNext(Node next) {        this.next = next;    }}////////////////////////////////////////package com.test.linkedlist;public class MyLinkedList {    private Node first;    private Node last;    private int size;    public void add(Object obj){        Node n = new Node();        if(first == null){            n.setPrevious(null);            n.setObj(obj);            n.setNext(null);            first = n;//第一个节点            last = n;//也是最后一个节点        }else{            //直接往last节点后增加新的节点            n.setPrevious(last);            n.setObj(obj);            n.setNext(null);            last.setNext(n);//之前的last指向下一个节点n(之后的last)            last = n;//n为最后一个节点        }        size++;    }    public int size(){        return size;    }    public Object get(int index){        Node temp = getNode(index);        return temp.obj;    }    //index越界处理    public void rangeCheck(int index){        if(index < 0 || index >= size){            try {                throw new Exception();            } catch (Exception e) {                e.printStackTrace();            }        }    }    public Node getNode(int index){//获得相应索引的节点        rangeCheck(index);        Node temp = null;        if(first != null){            temp = first;            for (int i = 0; i < index; i++) {//遍历节点                temp = temp.next;            }        }        return temp;    }    public void remove(int index){        Node temp = getNode(index);        if(temp != null){            Node up = temp.previous;            Node down = temp.next;            up.next = down;            down.previous = up;            size--;        }    }    public void add(int index,Object obj){        Node temp = getNode(index);        Node newNode = new Node();        newNode.obj = obj;        if(temp != null){            Node up = temp.previous;            up.next = newNode;            newNode.previous = up;            newNode.next = temp;            temp.previous = newNode;            size++;        }    }    public static void main(String[] args) {        MyLinkedList list = new MyLinkedList();        list.add("aaa");        list.add("bbb");        list.add("ccc");//      list.remove(1);        list.add(1, "BBB");        System.out.println(list.get(1));    }}