单向链表的java实现 详细讲解

链表的介绍

概念

链表是有序的列表，但是它在内存中是存储如下

小结:

1. 链表是以节点的方式来存储,是链式存储
2. 每个节点包含 data 域， next 域：指向下一个节点.
3. 如图：发现链表的各个节点不一定是连续存储.
4. 链表分带头节点的链表和没有头节点的链表，根据实际的需求来确定

单链表的应用实例

案例

使用带head头的单向链表实现 –水浒英雄排行榜管理完成对英雄人物的增删改查操作， 注: 删除和修改,查找

解题思路

1、增加

2、顺序添加（按照no由小到大排序）

3、修改和删除节点（原理差不多）

代码实现

1、新建英雄类，定义编号，名字，绰号，下一个节点的基本属性

class HeroNode{
    public int no;
    public String name;
    public String nickName;
    public HeroNode next;

    public HeroNode(){}

    public HeroNode(int no,String name,String nickName){
        this.no=no;
        this.name=name;
        this.nickName=nickName;
    }

    @Override
    public String toString() {
        return "HeroNode{" +
                "no=" + no +
                ", name='" + name + '\'' +
                ", nickName='" + nickName  +
                '}';
    }
}

2、新建LinkedList类，实现节点的增删改查方法

class SingleLinkedList{
    private HeroNode hero=new HeroNode(0,"","");
    public SingleLinkedList(){}

    //增加节点
    public void add(HeroNode heroNode){
        HeroNode temp=hero;
        while (true){
            if (temp.next==null){
                break;
            }
            temp=temp.next;
        }
        temp.next=heroNode;
    }

    //按照编号顺序排列
    public void addOrderly(HeroNode heroNode){
        HeroNode temp=hero;
        boolean isExist=false;  //判断该编号是否存在
        while (true){
            if (temp.next==null){
                break;
            }else if (temp.next.no>heroNode.no){
                break;
            }else if (temp.next.no==heroNode.no){
                isExist=true;
                break;
            }
            temp=temp.next;
        }

        if (isExist){
            System.out.println("该编号已存在~~~"+heroNode.no);
        }else{
            heroNode.next=temp.next;
            temp.next=heroNode;
        }
    }
    //遍历节点
    public void list(){
        HeroNode temp=hero;
        if (temp.next==null){
            System.out.println("未有节点信息~~~");
            return;
        }
        while (true){
            temp=temp.next;
            System.out.println(temp);
            if (temp.next==null){
                break;
            }
        }
    }

    //更新节点信息
    public void update(HeroNode newNode){
        if (hero.next==null){
            System.out.println("节点为空~~~");
            return;
        }

        boolean isFind=false;
        HeroNode temp=hero.next;

        while (true){
            if (temp.next==null){
                break;
            }else if (temp.next.no==newNode.no){
                isFind=true;
                break;
            }
            temp=temp.next;
        }

        if (isFind){
            temp.next.name=newNode.name;
            temp.next.nickName=newNode.nickName;
        }else{
            System.out.println("未找到该元素~~~");
        }
    }


    //删除节点信息
    public void delete(int no){
        if (hero.next==null){
            System.out.println("节点为空~~~");
            return;
        }

        boolean isFind=false;
        HeroNode temp=hero;

        while (true){
            if (temp.next==null){
                break;
            }else if (temp.next.no==no){
                isFind=true;
                break;
            }
            temp=temp.next;
        }

        if (isFind){
           temp.next=temp.next.next;
        }else{
            System.out.println("未找到该元素~~~");
        }
    }

}

3、代码整合，整合英雄类和linkedList类

package com.qf.linkedList;

public class SingleLinkedListDemo {
    public static void main(String[] args) {

        HeroNode heroNode1=new HeroNode(1,"宋江","及时雨");
        HeroNode heroNode2=new HeroNode(2,"卢俊义","玉麒麟");
        HeroNode heroNode3=new HeroNode(3,"吴用","智多星");
        HeroNode heroNode4=new HeroNode(4,"林冲","豹子头");

        SingleLinkedList singleLinkedList=new SingleLinkedList();
        //add 添加节点
      /*  singleLinkedList.add(heroNode3);
        singleLinkedList.add(heroNode4);
        singleLinkedList.add(heroNode1);
        singleLinkedList.add(heroNode2);
        singleLinkedList.list();*/

        //按照编号顺序添加节点
        singleLinkedList.addOrderly(heroNode3);
        singleLinkedList.addOrderly(heroNode4);
        singleLinkedList.addOrderly(heroNode1);
        singleLinkedList.addOrderly(heroNode2);
        singleLinkedList.list();

        //更新节点信息
        System.out.println("更新后的节点");
        HeroNode newNode=new HeroNode(3,"吴用new","智多星new");
        singleLinkedList.update(newNode);
        singleLinkedList.list();

        //删除节点信息
        System.out.println("删除后的节点");
        singleLinkedList.delete(3);
        singleLinkedList.delete(1);
        singleLinkedList.delete(2);
        singleLinkedList.list();
    }




}
class HeroNode{
    public int no;
    public String name;
    public String nickName;
    public HeroNode next;

    public HeroNode(){}

    public HeroNode(int no,String name,String nickName){
        this.no=no;
        this.name=name;
        this.nickName=nickName;
    }

    @Override
    public String toString() {
        return "HeroNode{" +
                "no=" + no +
                ", name='" + name + '\'' +
                ", nickName='" + nickName  +
                '}';
    }
}

class SingleLinkedList{
    private HeroNode hero=new HeroNode(0,"","");
    public SingleLinkedList(){}

    //增加节点
    public void add(HeroNode heroNode){
        HeroNode temp=hero;
        while (true){
            if (temp.next==null){
                break;
            }
            temp=temp.next;
        }
        temp.next=heroNode;
    }

    //按照编号顺序排列
    public void addOrderly(HeroNode heroNode){
        HeroNode temp=hero;
        boolean isExist=false;  //判断该编号是否存在
        while (true){
            if (temp.next==null){
                break;
            }else if (temp.next.no>heroNode.no){
                break;
            }else if (temp.next.no==heroNode.no){
                isExist=true;
                break;
            }
            temp=temp.next;
        }

        if (isExist){
            System.out.println("该编号已存在~~~"+heroNode.no);
        }else{
            heroNode.next=temp.next;
            temp.next=heroNode;
        }
    }
    //遍历节点
    public void list(){
        HeroNode temp=hero;
        if (temp.next==null){
            System.out.println("未有节点信息~~~");
            return;
        }
        while (true){
            temp=temp.next;
            System.out.println(temp);
            if (temp.next==null){
                break;
            }
        }
    }

    //更新节点信息
    public void update(HeroNode newNode){
        if (hero.next==null){
            System.out.println("节点为空~~~");
            return;
        }

        boolean isFind=false;
        HeroNode temp=hero.next;

        while (true){
            if (temp.next==null){
                break;
            }else if (temp.next.no==newNode.no){
                isFind=true;
                break;
            }
            temp=temp.next;
        }

        if (isFind){
            temp.next.name=newNode.name;
            temp.next.nickName=newNode.nickName;
        }else{
            System.out.println("未找到该元素~~~");
        }
    }


    //删除节点信息
    public void delete(int no){
        if (hero.next==null){
            System.out.println("节点为空~~~");
            return;
        }

        boolean isFind=false;
        HeroNode temp=hero;

        while (true){
            if (temp.next==null){
                break;
            }else if (temp.next.no==no){
                isFind=true;
                break;
            }
            temp=temp.next;
        }

        if (isFind){
           temp.next=temp.next.next;
        }else{
            System.out.println("未找到该元素~~~");
        }
    }

}

结果

1、add 添加节点

2、addOrderly（有序）添加节点

3、update 更新节点

4、delete 删除节点

如有不正确的，还请指出！！！