php类与对象简单操作

 <?php
 /*
  * Created on 2015-8-25
  *
  * To change the template for this generated file go to
  * Window - Preferences - PHPeclipse - PHP - Code Templates
  */
  class Type{

     var $username;
     public function getUserName(){

         return $this->username;

     }
     public function setUserName($username){
         $this->username = $username;

     }

  }
  class Free{
      private static $username;
      public static function getUser(){
          return Free::$username;
      }
      public static  function setUser($username){
          Free::$username = $username;

      }

  }
  $user = "link";
  Free::setUser($user);
  echo Free::getUser();
  $type = new Type();
  $type->setUserName("zhangming");
  echo $type->getUserName();
 ?>

初学php，望大家能多多纠正错误。