php只查询一次数据库分类表，实现无限极分类
数据库中字段和记录展示
$db = new Mysql();
$sql = 'select id,pid,name from test order by pid asc';
$result = $db->select($sql);
$result1 = $result;
$result 查询出来的数据格式
Array
(
[0] => Array
(
[id] => 67
[pid] => 0
[name] => 系统设置
)
[1] => Array
(
[id] => 76
[pid] => 0
[name] => 其他设置
)
[2] => Array
(
[id] => 73
[pid] => 0
[name] => 用户管理
)
[3] => Array
(
[id] => 72
[pid] => 67
[name] => 导航 管理
)
[4] => Array
(
[id] => 71
[pid] => 67
[name] => 菜单管理
)
...
) $maxNum = 1000;//设置最大循环次数
$count = -1;//设置计数
//默认根节点内容
$root = array(
'id' => '0',
'text' => 'root',
);
//辅助，主要作用用于检测节点是否存在
//注：下面使用的技巧都是使用对象的引用，赋值的不是一个具体值，而是一个引用
$existsMap = array(
'0' => &$root,
);
//结果记录的长度
$len = count($result1);
//计数
$num = 0;
//遍历结果集
while ($num < $len) {
$count++;
//如果计数器超过了最大循环次数就退出循环
if ($count > $maxNum) break;
$i = $count % $len;//取得下标，取莫的作用是防止下标超出边界
$obj = $result[$i];//取得当前节点
if (!$obj) continue;//不存在则跳过
$pidObj = & $existsMap[$obj['pid']];//检测辅助数组中是否有父节点数据并赋引用值给pidObj
if (!$pidObj) continue;
//如果存在pidObj，则设置当前节点在existsMap中
$existsMap[$obj['id']] = array(
'id' => $obj['id'],
'text' => $obj['name'],
);
//设置子节点
if (!$pidObj['children']) {
$pidObj['children'] = array();
}
//设置子节点为刚刚存在辅助数组中得引用
$pidObj['children'][] = & $existsMap[$obj['id']];
unset($result[$i]);
$num++;
}
//根据自己的需求，决定是否返回root节点
return $root['children'];输出$root结果：
Array
(
[id] => 0
[text] => root
[children] => Array
(
[0] => Array
(
[id] => 67
[text] => 系统设置
[children] => Array
(
[0] => Array
(
[id] => 72
[text] => 导航 管理
)
[1] => Array
(
[id] => 71
[text] => 菜单管理
)
[2] => Array
(
[id] => 70
[text] => 配置管理
)
[3] => Array
(
[id] => 69
[text] => 模型管理
)
[4] => Array
(
[id] => 68
[text] => 分类设置
)
)
)
[1] => Array
(
[id] => 76
[text] => 其他设置
[children] => Array
(
[0] => Array
(
[id] => 78
[text] => 其他设置2
)
[1] => Array
(
[id] => 77
[text] => 其他设置1
[children] => Array
(
[0] => Array
(
[id] => 79
[text] => 其他设置1-1
[children] => Array
(
[0] => Array
(
[id] => 81
[text] => 其他设置1-1-1
[children] => Array
(
[0] => Array
(
[id] => 82
[text] => 其他设置1-1-1-1
[children] => Array
(
[0] => Array
(
[id] => 87
[text] => 其他设置1-1-1-1-3
)
[1] => Array
(
[id] => 65
[text] => 其他设置1-1-1-1-2
)
[2] => Array
(
[id] => 83
[text] => 其他设置1-1-1-1-1
)
[3] => Array
(
[id] => 88
[text] => 其他设置1-1-1-1-4
)
)
)
)
)
)
)
[1] => Array
(
[id] => 80
[text] => 其他设置1-2
[children] => Array
(
[0] => Array
(
[id] => 84
[text] => 其他设置1-2-1
)
[1] => Array
(
[id] => 85
[text] => 其他设置1-2-2
)
)
)
)
)
)
)
[2] => Array
(
[id] => 73
[text] => 用户管理
[children] => Array
(
[0] => Array
(
[id] => 74
[text] => 用户列表
)
[1] => Array
(
[id] => 75
[text] => 权限分配
)
)
)
)
)前端效果展示
javascript写法：
var list = [{"id":"67","pid":"0","name":"\u7cfb\u7edf\u8bbe\u7f6e"},{"id":"76","pid":"0","name":"\u5176\u4ed6\u8bbe\u7f6e"},{"id":"73","pid":"0","name":"\u7528\u6237\u7ba1\u7406"},{"id":"72","pid":"67","name":"\u5bfc\u822a \u7ba1\u7406"},{"id":"71","pid":"67","name":"\u83dc\u5355\u7ba1\u7406"},{"id":"70","pid":"67","name":"\u914d\u7f6e\u7ba1\u7406"},{"id":"69","pid":"67","name":"\u6a21\u578b\u7ba1\u7406"},{"id":"68","pid":"67","name":"\u5206\u7c7b\u8bbe\u7f6e"},{"id":"74","pid":"73","name":"\u7528\u6237\u5217\u8868"},{"id":"75","pid":"73","name":"\u6743\u9650\u5206\u914d"},{"id":"78","pid":"76","name":"\u5176\u4ed6\u8bbe\u7f6e2"},{"id":"77","pid":"76","name":"\u5176\u4ed6\u8bbe\u7f6e1"},{"id":"79","pid":"77","name":"\u5176\u4ed6\u8bbe\u7f6e1-1"},{"id":"80","pid":"77","name":"\u5176\u4ed6\u8bbe\u7f6e1-2"},{"id":"81","pid":"79","name":"\u5176\u4ed6\u8bbe\u7f6e1-1-1"},{"id":"84","pid":"80","name":"\u5176\u4ed6\u8bbe\u7f6e1-2-1"},{"id":"85","pid":"80","name":"\u5176\u4ed6\u8bbe\u7f6e1-2-2"},{"id":"82","pid":"81","name":"\u5176\u4ed6\u8bbe\u7f6e1-1-1-1"},{"id":"87","pid":"82","name":"\u5176\u4ed6\u8bbe\u7f6e1-1-1-1-3"},{"id":"65","pid":"82","name":"\u5176\u4ed6\u8bbe\u7f6e1-1-1-1-2"},{"id":"83","pid":"82","name":"\u5176\u4ed6\u8bbe\u7f6e1-1-1-1-1"},{"id":"88","pid":"82","name":"\u5176\u4ed6\u8bbe\u7f6e1-1-1-1-4"}];
var maxNum = 1000;
var count = -1;
var root = {id:"0", text:"root"};
var existsMap = {"0":root};
var len = list.length;
var num = 0;
while(num < len) {
count ++;
if(maxNum < count) {
break;
}
var i = count % len;
var obj = list[i];
if(obj == -1) {
continue;
}
var pidObj = existsMap[obj.pid];
if(pidObj == null) {
continue;
}
var treeNode = {id:obj.id, text:obj.name};
existsMap[obj.id] = treeNode;
if(pidObj['children'] == null) {
pidObj['children'] = [];
}
pidObj['children'].push(treeNode);
list[i] = -1;
num ++;
}
console.log(root)总结：要点就是使用对象的引用