1.首先在Vendor下新建SendAllMsg文件夾，然后將SendAllMsg.php放入

SendAllMsg.php

<?php
/*
+----------------------------------------------------------------------
+ Title        : 微信公眾號無線群發接口
+ Author      : wjwer
+ Version      : 1.0
+ Initial-Time : 2017.3.20
+ Last-time    : 2017.3.20 wjwer
+ Desc        :  使用說明:微信公眾號無線群發接口，使用實例:
$test = new \SendAllMsg(C('WX_APPID'),C('WX_CRYPT'));
$test->sendMsgToAll();  //調用群發方法
注：1.使用條件：認證號或測試號
2.群發消息內容可為圖文、文本、音樂等,$data具體內容參照微信開發文檔/客服接口
3.若用戶量過萬,需修改getUserInfo()，具體參照信開發文檔/獲取關注者列表
+Ps  : 參考文檔  https://mp.weixin.qq.com/wiki/15/40b6865b893947b764e2de8e4a1fb55f.html
+----------------------------------------------------------------------
*/
interface iSendAllMsg{
    function getData($url);  //curl 發送get請求
    function postData($url,$data);  //curl 發送post請求
    function getAccessToken();  //在構造方法中已調用該方法來獲取access_token,注                意它在wx服務器的保存時間7200s
    function sendMsgToAll();  //群發消息方法,發送的消息$data 可自行修改
}
class SendAllMsg implements iSendAllMsg{
  private $appId;
  private $appSecret;
  private $access_token;
  public function __construct($appId, $appSecret) {
  $this->appId = $appId;
  $this->appSecret = $appSecret;
  $this->access_token = $this->getAccessToken();
}
function getData($url){
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  curl_setopt($ch, CURLOPT_HEADER, 0);
  curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (compatible; MSIE 5.01; Windows NT 5.0)');
  curl_setopt($ch, CURLOPT_ENCODING, 'gzip');
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
  $data = curl_exec($ch);
  curl_close($ch);
  return $data;
}
function postData($url,$data){
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
  curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
  curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (compatible; MSIE 5.01;   Windows NT 5.0)');
  curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
  curl_setopt($ch, CURLOPT_AUTOREFERER, 1);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  $tmpInfo = curl_exec($ch);
if (curl_errno($ch)) {
  return curl_error($ch);
}
  curl_close($ch);
  return $tmpInfo;
}
function getAccessToken(){
  $url = "https://api.weixin.qq.com/cgi-bin/token?  grant_type=client_credential&appid=".$this->appId."&secret=".$this->appSecret;
  $res = $this->getData($url);
  $jres = json_decode($res,true);
  $access_token = $jres['access_token'];
  return $access_token;
}
private function getUserInfo(){
  $url = "https://api.weixin.qq.com/cgi-bin/user/get?access_token=".$this->access_token;
  $res = $this->getData($url);
  $jres = json_decode($res,true);
//print_r($jres);
  $userInfoList = $jres['data']['openid'];
  return $userInfoList;
}
function sendMsgToAll(){
  $userInfoList = $this->getUserInfo();
  $url = "https://api.weixin.qq.com/cgi-bin/message/custom/send?    access_token=".$this->access_token;
  foreach($userInfoList as $val){
  $data = '{
  "touser":"'.$val.'",
  "msgtype":"text",
  "text":
{
  "content":"再來一次"
}
}';
  $this->postData($url,$data);
}
}
}
?>

在控制器中調用：

<?php
namespace Admin\Controller;
use Think\Controller;
header('Content-Type:text/html; charset= utf-8');
class CeshiController extends PublicController{
    
    public function index(){
        //微信群發
        Vendor('SendAllMsg.SendAllMsg');
        $test = new \SendAllMsg(C('WX_APPID'),C('WX_CRYPT'));
        $test->sendMsgToAll();  //調用群發方法
        
    }

}

順帶把發送其他消息的也說一下吧

微信客服接口總摘取

各消息類型所需的JSON數據包如下：
發送文本消息

    "touser":"OPENID",
    "msgtype":"text",
    "text":
    {
         "content":"Hello World"
    }
}

發送圖片消息

{
    "touser":"OPENID",
    "msgtype":"image",
    "image":
    {
      "media_id":"MEDIA_ID"
    }
}

發送語音消息

{
    "touser":"OPENID",
    "msgtype":"voice",
    "voice":
    {
      "media_id":"MEDIA_ID"
    }
}

發送視頻消息

{
    "touser":"OPENID",
    "msgtype":"video",
    "video":
    {
      "media_id":"MEDIA_ID",
      "thumb_media_id":"MEDIA_ID",
      "title":"TITLE",
      "description":"DESCRIPTION"
    }
}

發送音樂消息

{
    "touser":"OPENID",
    "msgtype":"music",
    "music":
    {
      "title":"MUSIC_TITLE",
      "description":"MUSIC_DESCRIPTION",
      "musicurl":"MUSIC_URL",
      "hqmusicurl":"HQ_MUSIC_URL",
      "thumb_media_id":"THUMB_MEDIA_ID" 
    }
}

發送圖文消息（點擊跳轉到外鏈） 圖文消息條數限制在8條以內，注意，如果圖文數超過8，則將會無響應。

{
    "touser":"OPENID",
    "msgtype":"news",
    "news":{
        "articles": [
         {
             "title":"Happy Day",
             "description":"Is Really A Happy Day",
             "url":"URL",
             "picurl":"PIC_URL"
         },
         {
             "title":"Happy Day",
             "description":"Is Really A Happy Day",
             "url":"URL",
             "picurl":"PIC_URL"
         }
         ]
    }
}

發送圖文消息（點擊跳轉到圖文消息頁面） 圖文消息條數限制在8條以內，注意，如果圖文數超過8，則將會無響應。

{
    "touser":"OPENID",
    "msgtype":"mpnews",
    "mpnews":
    {
         "media_id":"MEDIA_ID"
    }
}

發送卡券

{
  "touser":"OPENID", 
  "msgtype":"wxcard",
  "wxcard":{              
           "card_id":"123dsdajkasd231jhksad"        
            },
}