PHP学习：php实现无限级分类（递归方法）

create table onepiece(
  id int auto_increment,
  pid int not null,
  name varchar(225) not null,
  primary key(id)
);

insert onepiece values
  (1,0,'海军'),
  (2,0,'海贼'),
  (3,0,'革命军'),
  (4,1,'青雉'),
  (5,1,'赤犬'),
  (6,1,'黄猿'),
  (7,2,'四皇'),
  (8,2,'七武海'),
  (9,2,'草帽海贼团'),
  (10,9,'索隆'),
  (11,7,'香克斯'),
  (12,8,'多弗朗明哥'),
  (13,8,'克洛克达尔');

<?php
class Unlimited{
  protected $mysqli;
  public function __construct($config){
    $this->mysqli=new mysqli($config['host'],$config['user'],$config['pwd']);
    $this->mysqli->select_db($config['db']);
    $this->mysqli->set_charset('utf8');
    if ($this->mysqli->connect_errno) {
      echo $this->mysqli->connect_error;
    }
  }  
  private function getList($pid=0,&$result=array(),$spac=0){
    $spac=$spac+2;
    $sql="select * from onepiece where pid={$pid}";
    $rs=$this->mysqli->query($sql);
    while($row=$rs->fetch_assoc()) {
      $row['name']=str_repeat(' &nbsp',$spac).$row['name'];
      $result[]=$row;
      $this->getList($row['id'],$result,$spac);      
    }
    return $result;
  }
  /**
   * 展现下拉列表式分类
   * @return [type] 
   */
  public function displayList(){
    $rs=$this->getList();
    $str="<select name='cate'>";
    foreach ($rs as $key => $val) {
      $str.="<option >{$val['name']}</option>";
    }
    $str.="</select>";
    return $str;
  }
  private function getLink($cid,&$result=array()){
    $sql="select * from onepiece where id={$cid}";
    $rs=$this->mysqli->query($sql);
    if($row=$rs->fetch_assoc()){
      $result[]=$row;
      $this->getLink($row['pid'],$result);
    }
    return array_reverse($result);
  }
  /**
   * 展现导航Link
   * @param [type] $cid [description]
   * @return [type]   [description]
   */
  public function displayLink($cid){
    $rs=$this->getLink($cid);
    $str='';
    foreach ($rs as $val) {
      $str.="<a href=''>{$val['name']}</a>>";
    }
    return $str;
  }
  /**
   * 增加分类
   * @param [type] $pid 父类id
   * @param [type] $name 本类名
   */
  public function addNodes($pid,$name){
    $sql="insert into onepiece values('',{$pid},'".$name."')";
    if($this->mysqli->query($sql)){
      return true;
    }
  }
  /**
   * 删除分类
   * @param [type] $id 本类id
   * @return [type]   
   */
  public function deleteNodes($id){
    $sql="select * from onepiece where pid ={$id}";
    $rs=$this->mysqli->query($sql);
    if($row=$rs->fetch_assoc()){
      $mes="还有子元素,请勿删除";
    }else{
      $sql="delete from onepiece where id={$id}";
      if($this->mysqli->query($sql)){
        $mes="删除成功";
      }
    }
    return $mes;
  }
}

CREATE TABLE IF NOT EXISTS `category` ( 
 `categoryId` smallint(5) unsigned NOT NULL AUTO_INCREMENT, 
 `parentId` smallint(5) unsigned NOT NULL DEFAULT '0', 
 `categoryName` varchar(50) NOT NULL, 
 PRIMARY KEY (`categoryId`) 
) ; 

INSERT INTO `category` (`categoryId`, `parentId`, `categoryName`) VALUES 
(1, 0, 'php'), 
(2, 0, 'java'), 
(3, 0, 'c/c++'), 
(4, 1, 'php基础'), 
(5, 1, 'php开源资料'), 
(6, 1, 'php框架'), 
(7, 2, 'java Se'), 
(8, 2, 'java EE'), 
(9, 2, 'java Me'), 
(10, 3, 'c/c++基础编程'), 
(11, 3, 'c/c++系统开发'), 
(12, 3, 'c嵌入式编程'), 
(13, 3, 'c++应用开发'), 
(14, 13, 'c++桌面应用开发'), 
(15, 13, 'c++游戏开发'); 

<?php 
/* 
php无限极分类 
*/ 
 
//获取某分类的直接子分类 
function getSons($categorys,$catId=0){ 
  $sons=array(); 
  foreach($categorys as $item){ 
    if($item['parentId']==$catId) 
      $sons[]=$item; 
  } 
  return $sons; 
} 
 
//获取某个分类的所有子分类 
function getSubs($categorys,$catId=0,$level=1){ 
  $subs=array(); 
  foreach($categorys as $item){ 
    if($item['parentId']==$catId){ 
      $item['level']=$level; 
      $subs[]=$item; 
      $subs=array_merge($subs,getSubs($categorys,$item['categoryId'],$level+1)); 
       
    } 
       
  } 
  return $subs; 
} 
 
//获取某个分类的所有父分类 
//办法一,递归 
function getParents($categorys,$catId){ 
  $tree=array(); 
  foreach($categorys as $item){ 
    if($item['categoryId']==$catId){ 
      if($item['parentId']>0) 
        $tree=array_merge($tree,getParents($categorys,$item['parentId'])); 
      $tree[]=$item;  
      break;  
    } 
  } 
  return $tree; 
} 
 
//办法二,迭代 
function getParents2($categorys,$catId){ 
  $tree=array(); 
  while($catId != 0){ 
    foreach($categorys as $item){ 
      if($item['categoryId']==$catId){ 
        $tree[]=$item; 
        $catId=$item['parentId']; 
        break;  
      } 
    } 
  } 
  return $tree; 
} 
//测试 部分 
$pdo=new PDO('mysql:host=localhost;dbname=test','root','8888'); 
$stmt=$pdo->query("select * from category order by categoryId"); 
$categorys=$stmt->fetchAll(PDO::FETCH_ASSOC); 
 
$result=getSons($categorys,1); 
foreach($result as $item) 
  echo $item['categoryName'].'<br>'; 
echo '<hr>'; 
 
$result=getSubs($categorys,0); 
foreach($result as $item) 
  echo str_repeat(' ',$item['level']).$item['categoryName'].'<br>'; 
echo '<hr>'; 
 
$result=getParents($categorys,7); 
foreach($result as $item) 
  echo $item['categoryName'].' >> '; 
echo '<hr>'; 
 
$result=getParents2($categorys,15); 
foreach($result as $item) 
  echo $item['categoryName'].' >> '; 
?>