格式化节点树的类,写得不好,没有算法,但可以用

将数据库取的分类数据格式化,如:

新闻
--体育新闻
--娱乐新闻
财经
--外汇
--金融

class tree
{

    /**原始数据*/
	public    $original;

    /**id的键名*/
    public    $id;

    /**父id的键名*/
    public    $parentId;

    /**初始化时的id*/
    protected $initId;

    /**节点的级别*/
    protected $thisLevel = 0;

    /**最终树*/
    protected $tree = array();


   /**
     * 构造函数
	 +------------------------------------------
	 * @access  public
	 +------------------------------------------
	 * @param   array    $original    原始数据
	 * @param   string   $id          id的键名
	 * @param   string   $parentId    父id的键名
	 +------------------------------------------
	 * @return  void
	 */
    public function __construct($original='',$id='',$parentId='')
	{
          if($original && $id && $parentId)
		  {
		     $this->initialize($original,$id,$parentId);
		  }
    }


   /**
     * 初始化
	 +------------------------------------------
	 * @access  public
	 +------------------------------------------
	 * @param   array    $original    原始数据
	 * @param   string   $id          id的键名
	 * @param   string   $parentId    父id的键名
	 +------------------------------------------
	 * @return  void
	 */
    public function initialize($original,$id,$parentId)
	{
          $this->original = $original;
		  $this->id       = $id;
		  $this->parentId = $parentId;
    }


   /**
     * 获取初始节点
	 +----------------------------------------------
	 * @access  protected
	 +----------------------------------------------
	 * @param   int      $parentId       初始节点的级别
	 +----------------------------------------------
	 * @return  array    $parentTree
	 */
    protected function getParentTree($parentId)
	{
		  $parentTree = array();

          foreach($this->original as $key=>$value)
		  {
		       if($value[$this->parentId] == $parentId)
			   {
				    array_push($parentTree,$value);
			   }
		  }

		  return $parentTree;
 	}


   /**
     * 获取子树
	 +----------------------------------------------
	 * @access  protected
	 +----------------------------------------------
	 * @param   int      $id              节点的id
	 * @param   string   $levelTag        缩进标记
	 +----------------------------------------------
	 * @return  void
	 */
    protected function getChildrenTree($id,$levelTag)
	{
		  foreach($this->original as $key=>$value)
		  {
		       if($id == $value[$this->parentId])
	           {
				   if($levelTag)
			       {
					   $this->getLevel($value[$this->parentId]);
				       $value['levelTag'] = str_repeat($levelTag,$this->thisLevel);
					   $this->thisLevel = 0;
   				   }
				   $this->tree[] = $value;
				   $this->getChildrenTree($value[$this->id],$levelTag);
		       }
		  }
 	}


   /**
     * 获取节点的级别
	 +-------------------------------------------------
	 * @access  protected
	 +-------------------------------------------------
	 * @param   int      $parentId        节点的父id
	 +-------------------------------------------------
	 * @return  void
	 */
    protected function getLevel($parentId)
	{
		  foreach($this->original as $key=>$value)
		  {
		       if($parentId == $value[$this->id] && $parentId != $this->initId)
	           {
				   $this->thisLevel++;
				   $this->getLevel($value[$this->parentId]);
		       }
		  }
   	}


   /**
     * 获取完整的树
	 +-------------------------------------------------
	 * @access  public
	 +-------------------------------------------------
	 * @param   int      $level      从什么级别开始获取
	 * @param   string   $levelTag   缩进标记
	 +-------------------------------------------------
	 * @return  array    $this->tree      完整的树
	 */
    public function getTree($parentId=0,$levelTag='')
	{
		  $this->initId = $parentId;
          $parentTree   = $this->getParentTree($parentId);

   		  foreach($parentTree as $key=>$value)
		  {
			   $this->tree[] = $value;
		       $this->getChildrenTree($value[$this->id],$levelTag);
		  }

		  return $this->tree;
  	}

}




$conf =  array(
	       1 => array('id'=>'1','parentid'=>0,'name'=>'1'),
	       2 => array('id'=>'2','parentid'=>0,'name'=>'2'),
	       3 => array('id'=>'3','parentid'=>1,'name'=>'1-1'),
	       4 => array('id'=>'4','parentid'=>1,'name'=>'1-2'),
	       5 => array('id'=>'5','parentid'=>2,'name'=>'2-1'),
	       6 => array('id'=>'6','parentid'=>3,'name'=>'1-1-1'),
           7 => array('id'=>'7','parentid'=>4,'name'=>'1-2-1'),
		   8 => array('id'=>'8','parentid'=>5,'name'=>'2-1-1'),
		   9 => array('id'=>'9','parentid'=>8,'name'=>'2-1-1-1')
	       );

$tree = new tree($conf,'id','parentid');
$arr = $tree->getTree(0,'   ');
foreach($arr as $val)
{
  if($val['levelTag'])
  {
     echo $val['levelTag'].'|- ';
  }
  echo $val['name'].'';
}

?>

class tree
{

    /**原始数据*/
	public    $original;

    /**id的键名*/
    public    $id;

    /**父id的键名*/
    public    $parentId;

    /**初始化时的id*/
    protected $initId;

    /**节点的级别*/
    protected $thisLevel = 0;

    /**最终树*/
    protected $tree = array();


   /**
     * 构造函数
	 +------------------------------------------
	 * @access  public
	 +------------------------------------------
	 * @param   array    $original    原始数据
	 * @param   string   $id          id的键名
	 * @param   string   $parentId    父id的键名
	 +------------------------------------------
	 * @return  void
	 */
    public function __construct($original='',$id='',$parentId='')
	{
          if($original && $id && $parentId)
		  {
		     $this->initialize($original,$id,$parentId);
		  }
    }


   /**
     * 初始化
	 +------------------------------------------
	 * @access  public
	 +------------------------------------------
	 * @param   array    $original    原始数据
	 * @param   string   $id          id的键名
	 * @param   string   $parentId    父id的键名
	 +------------------------------------------
	 * @return  void
	 */
    public function initialize($original,$id,$parentId)
	{
          $this->original = $original;
		  $this->id       = $id;
		  $this->parentId = $parentId;
    }


   /**
     * 获取初始节点
	 +----------------------------------------------
	 * @access  protected
	 +----------------------------------------------
	 * @param   int      $parentId       初始节点的级别
	 +----------------------------------------------
	 * @return  array    $parentTree
	 */
    protected function getParentTree($parentId)
	{
		  $parentTree = array();

          foreach($this->original as $key=>$value)
		  {
		       if($value[$this->parentId] == $parentId)
			   {
				    array_push($parentTree,$value);
			   }
		  }

		  return $parentTree;
 	}


   /**
     * 获取子树
	 +----------------------------------------------
	 * @access  protected
	 +----------------------------------------------
	 * @param   int      $id              节点的id
	 * @param   string   $levelTag        缩进标记
	 +----------------------------------------------
	 * @return  void
	 */
    protected function getChildrenTree($id,$levelTag)
	{
		  foreach($this->original as $key=>$value)
		  {
		       if($id == $value[$this->parentId])
	           {
				   if($levelTag)
			       {
					   $this->getLevel($value[$this->parentId]);
				       $value['levelTag'] = str_repeat($levelTag,$this->thisLevel);
					   $this->thisLevel = 0;
   				   }
				   $this->tree[] = $value;
				   $this->getChildrenTree($value[$this->id],$levelTag);
		       }
		  }
 	}


   /**
     * 获取节点的级别
	 +-------------------------------------------------
	 * @access  protected
	 +-------------------------------------------------
	 * @param   int      $parentId        节点的父id
	 +-------------------------------------------------
	 * @return  void
	 */
    protected function getLevel($parentId)
	{
		  foreach($this->original as $key=>$value)
		  {
		       if($parentId == $value[$this->id] && $parentId != $this->initId)
	           {
				   $this->thisLevel++;
				   $this->getLevel($value[$this->parentId]);
		       }
		  }
   	}


   /**
     * 获取完整的树
	 +-------------------------------------------------
	 * @access  public
	 +-------------------------------------------------
	 * @param   int      $level      从什么级别开始获取
	 * @param   string   $levelTag   缩进标记
	 +-------------------------------------------------
	 * @return  array    $this->tree      完整的树
	 */
    public function getTree($parentId=0,$levelTag='')
	{
		  $this->initId = $parentId;
          $parentTree   = $this->getParentTree($parentId);

   		  foreach($parentTree as $key=>$value)
		  {
			   $this->tree[] = $value;
		       $this->getChildrenTree($value[$this->id],$levelTag);
		  }

		  return $this->tree;
  	}

}




$conf =  array(
	       1 => array('id'=>'1','parentid'=>0,'name'=>'1'),
	       2 => array('id'=>'2','parentid'=>0,'name'=>'2'),
	       3 => array('id'=>'3','parentid'=>1,'name'=>'1-1'),
	       4 => array('id'=>'4','parentid'=>1,'name'=>'1-2'),
	       5 => array('id'=>'5','parentid'=>2,'name'=>'2-1'),
	       6 => array('id'=>'6','parentid'=>3,'name'=>'1-1-1'),
           7 => array('id'=>'7','parentid'=>4,'name'=>'1-2-1'),
		   8 => array('id'=>'8','parentid'=>5,'name'=>'2-1-1'),
		   9 => array('id'=>'9','parentid'=>8,'name'=>'2-1-1-1')
	       );

$tree = new tree($conf,'id','parentid');
$arr = $tree->getTree(0,'   ');
foreach($arr as $val)
{
  if($val['levelTag'])
  {
     echo $val['levelTag'].'|- ';
  }
  echo $val['name'].'';
}

?>