java中如何实现链表

java中就用类来实现链表结构,每个节点都是类似的，所以next就是类本身的对象。
下面是用链表来实现一个输入字符的功能

package MyFirstPackage;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class MyLinkNote {

	public static void main(String[] args) {
		JFrame w=new JFrame();
		w.setSize(600,500);
		w.setLocationRelativeTo(null);
		
		MyLinkNotePanel mlnp=new MyLinkNotePanel();
		w.add(mlnp);
		w.addKeyListener(mlnp);
		mlnp.addKeyListener(mlnp);
		w.setVisible(true);
	}

}

class MyLinkNotePanel extends JPanel implements KeyListener{
	Node firstNode=new Node();
	Node nowNode=firstNode;
	int l=0;
	public void paint(Graphics g){
		super.paint(g);
		Node tmpNode=firstNode;
		int x=0;
		while(tmpNode.next!=null){
			g.drawString(new Character(tmpNode.next.value).toString(), 10+x*8, 15);
			tmpNode=tmpNode.next;
			x++;
		}
		g.drawLine(10+l*8, 5, 10+l*8, 15);
	}
	@Override
	public void keyTyped(KeyEvent e) {
		
	}

	@Override
	public void keyPressed(KeyEvent e) {
		int code=e.getKeyCode();
		if(code>=KeyEvent.VK_A && code<=KeyEvent.VK_Z){
			Node newNode=new Node();
			newNode.value=e.getKeyChar();
			
			if(nowNode.next!=null){//从中间插入字符的情况
				newNode.next=nowNode.next;
			}
			nowNode.next=newNode;
			nowNode=newNode;
			l++;
		}
		
		if(code==KeyEvent.VK_LEFT){//向左移动光标
			if(l>0){
				l--;
				Node tmNode=firstNode;
				while(tmNode.next!=nowNode){
					tmNode=tmNode.next;
				}
				nowNode=tmNode;
			}
		}
		if(code==KeyEvent.VK_RIGHT){//向右移动光标
			if(nowNode.next!=null){
				l++;
				nowNode=nowNode.next;
			}
		}
		
		
		repaint();
	}

	@Override
	public void keyReleased(KeyEvent e) {
		
	}
	
}

class Node{
	public char value=' ';
	public Node next=null;
}

}