环境：layui2.9.21\thinkphp8.1

前端代码：

layui.use(['upload', 'layer'], function() {
        const upload = layui.upload;
        const layer = layui.layer;
        const $ = layui.$;

        // 上传图片
        const uploadInstImage = upload.render({
            elem: '#uploadImage',
            url: '/admin/demo/uploadImage', // 上传接口
            accept: 'images', // 只允许上传图片
            multiple: true,  // 开启多文件上传;
            unified: true,   // 统一上传,只请求后端api一次;
            field: 'file[]', // 一定要带上[];
            done: function (res) {
                if (res.code === 0) {
                    $('#imagePath').val(res.data.path); // 将路径填入隐藏字段
                    layer.msg('上传成功');
                } else {
                    layer.msg('上传失败：' + res.msg);
                }
            },
            error: function () {
                layer.msg('上传失败，请重试');
            }
        });
    });

后端代码：

use think\facade\Filesystem;
use think\response\Json;
use think\response\View;
use app\admin\validate\Upload; // 创建了图片上传验证器;

public function uploadImage(): Json
    {
        $files = request()->file('file'); // 一定和前端的字段名称保持一致;
        $validate = new Upload();
        $result = $validate->check(['image' => $files]);
        if (!$result) {
            return json(['code' => 500, 'msg' => $validate->getError()]);
        }
        try {
            $filepath = []; // 存储上传成功后的文件路径,以数组的形式保存;
            // 遍历$files
            foreach ($files as $file) {
                $filepath[] = Filesystem::disk('public')->putFile('', $file);
            }
            return json(['code' => 200, 'msg' => 'success', 'data' => ['path' => str_replace('\\', '/', $filepath)]]);
        } catch (\Exception $e){
            return json(['code' => 500, 'msg' => $e->getMessage()]);
        }
    }