<?php
set_time_limit(0);

index();

function index()
{
    $list=getNext("http://www.stats.gov.cn/tjsj/tjbz/tjyqhdmhcxhfdm/2020/index.html",'',1);
    file_put_contents('area.json',json_encode($list,JSON_UNESCAPED_UNICODE));
}

function getNext($parent_url,$next_page,$level)
{
    usleep(20*1000);
    $isLast=0;
    $parent_url_arr=explode('/',$parent_url);
    unset($parent_url_arr[count($parent_url_arr)-1]);
    $parent_url_2=implode('/',$parent_url_arr);
    $next_url=$parent_url_2.'/'.$next_page;

    $html=file_get_contents($next_url);
    if (!$html){
        echo '超时'."\n";
        sleep(10);
        $html=file_get_contents($next_url);
        if ($html){
            echo '继续'."\n";
        }
    }

    $html=iconv('GB2312', 'UTF-8', $html);

    if ($level==1){
        preg_match_all("/<a href='(.*?\.html)'>(.*?)</",$html,$r);
    }else{
        preg_match_all("/<td><a href='(.{1,50}\.html)'>(.*?)<\/a><\/td><td><a href='.*?'>(.*?)<\/a/",$html,$r);
    }
    if (count($r[0])==0){
        preg_match_all("/<tr class='.{1,20}'><td>(.{1,20})<\/td><td>(.{1,20})<\/td><td>(.{1,30})<\/td><\/tr>/",$html,$r);
        $isLast=1;
    }

    if ($level==1){
        $list['href']=$r[1];
        $list['name']=$r[2];
        $list['code']='';
        $list['cityclass']='';
    }else{
        if ($isLast==0){
            $list['href']=$r[1];
            $list['name']=$r[3];
            $list['code']=$r[2];
            $list['cityclass']='';
        }else{
            $list['href']=[];
            $list['name']=$r[3];
            $list['code']=$r[1];
            $list['cityclass']=$r[2];
        }
    }
    $list['level']=$level;
    $list['list']=[];
    if ($level<=3){ // 不用爬太深
        foreach ($list['href'] as $key=>$v){
            if ($list['level']==1){
                echo $list['name'][$key]."\n";
            }
            $data=[
                'code'=>$list['code'][$key],
                'cityclass'=>$list['cityclass'][$key],
                'name'=>$list['name'][$key],
                'children'=>[]
            ];
            $data['children']=getNext($next_url,$list['href'][$key],$level+1);
            $list['list'][]=$data;
        }
    }
    return $list['list'];
}

用PHP命令行执行，然后坐等生成json文件就行。