Java Arraylist排序

import java.util.*;   
  
public class Test {   
  
public static void main(String[] args){   
  List<Point> points=new ArrayList<Point>();   
     
  Point point1=new Point();   
  point1.setX(1324);   
  point1.setY(345);   
  point1.setZ(436);   
  points.add(point1);   
     
  Point point2=new Point();   
  point2.setX(23);   
  point2.setY(8941.656);   
  point2.setZ(431412);   
  points.add(point2);   
     
  Point point3=new Point();   
  point3.setX(786584);   
  point3.setY(23452);   
  point3.setZ(43563);   
  points.add(point3);   
     
  //根据X排序   
  Collections.sort(points,new SortByX());   
     
  for(Point p:points){   
   System.out.print(p.getX()+"\t"+p.getY()+"\t"+p.getZ());   
   System.out.println();   
  }   
     
  //根据Y排序   
//  Collections.sort(points,new SortByY());   
//     
//  for(Point p:points){   
//   System.out.print(p.getX()+"\t"+p.getY()+"\t"+p.getZ());   
//   System.out.println();   
//  }   
//     
//  //根据Z排序   
//  Collections.sort(points,new SortByZ());   
//     
//  for(Point p:points){   
//   System.out.print(p.getX()+"\t"+p.getY()+"\t"+p.getZ());   
//   System.out.println();   
//  }   
}   
  
}   
  
class Point{   
private double x;   
private double y;   
private double z;   
public double getX() {   
  return x;   
}   
public void setX(double x) {   
  this.x = x;   
}   
public double getY() {   
  return y;   
}   
public void setY(double y) {   
  this.y = y;   
}   
public double getZ() {   
  return z;   
}   
public void setZ(double z) {   
  this.z = z;   
}   
public Point(){}   
}   
  
//根据X排序   
class SortByX implements Comparator{   
public int compare(Object obj1,Object obj2){   
  Point point1=(Point)obj1;   
  Point point2=(Point)obj2;   
  if(point1.getX()>point2.getX())   
   return 1;   
  else  
   return 0;   
}   
}   
//根据Y排序   
class SortByY implements Comparator{   
public int compare(Object obj1,Object obj2){   
  Point point1=(Point)obj1;   
  Point point2=(Point)obj2;   
  if(point1.getY()>point2.getY())   
   return 1;   
  else  
   return 0;   
}   
}   
//根据Z排序   
class SortByZ implements Comparator{   
public int compare(Object obj1,Object obj2){   
  Point point1=(Point)obj1;   
  Point point2=(Point)obj2;   
  if(point1.getZ()>point2.getZ())   
   return 1;   
  else  
   return 0;   
}   
}