php之无限极分类

首先建立分类信息表：

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`)
)  ;

插入若干数据：

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
//方法一，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;
}

//方法二,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'].' >> ';

?>