根据点画线java

 package com.yang;

 import java.awt.Color;
 import java.awt.Graphics;
 import java.util.ArrayList;
 import java.util.List;

 import javax.swing.JFrame;
 import javax.swing.JPanel;

 public class drawlineforspline extends JFrame{

     private static final long serialVersionUID = 1L;
     static List <mypoint>plist;
     public static class mypoint{
         int x;
         int y;
         public mypoint(int x,int y){
             this.x=x;
             this.y=y;
         }
     }
     public drawlineforspline(){
         init();
     }
     public drawlineforspline(ArrayList plist){
         init();
         this.plist=plist;

     }
     private void init(){

         this.setTitle("drawline");
         this.setBounds(200, 200, 500, 400);
         this.setBackground(Color.white);
         this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         this.setLocationRelativeTo(null);
         this.setVisible(true); 

         plist =new ArrayList();
         plist.add(new mypoint(50,80));
         plist.add(new mypoint(50,120));
         plist.add(new mypoint(80,50));
         plist.add(new mypoint(150,10));
         plist.add(new mypoint(180,80));
         plist.add(new mypoint(230,200));

     }

     public class Mypanel extends JPanel{
         public void paint(Graphics g){
             mypoint fromP=new mypoint(50,80);
             mypoint toP=new mypoint(370,240);
             for(int i=0;i<plist.size()-1;i++){
                 g.drawLine(plist.get(i).x, plist.get(i).y, plist.get(i+1).x, plist.get(i+1).y);
             }
         }
     }

     public static void main(String[] args) {
         drawlineforspline d=new drawlineforspline();
         Mypanel myp=d.new Mypanel();
         d.add(myp);
     }

 }