调整admin下的类库代码，将主要逻辑调整到extend下

extend/base/admin/controller/LoginClass.php

@@ -0,0 +1,96 @@
+<?php
+
+namespace base\admin\controller;
+
+use app\admin\model\SystemAdmin;
+use app\common\controller\AdminController;
+use think\captcha\facade\Captcha;
+use think\facade\Env;
+use think\facade\Event;
+
+/**
+ * Class Login.
+ */
+class LoginClass extends AdminController
+{
+    /**
+     * 初始化方法.
+     */
+    public function initialize()
+    {
+        parent::initialize();
+        $action = $this->request->action();
+        if (!empty(session('admin')) && !in_array($action, ['out'])) {
+            $adminModuleName = config('app.admin_alias_name');
+            $this->success('已登录，无需再次登录', [], __url("@{$adminModuleName}"));
+        }
+    }
+
+    /**
+     * 用户登录.
+     * @return string
+     * @throws \Exception
+     */
+    public function index()
+    {
+        event_response('AdminLoginIndex', [
+            'controller' => $this,
+        ]);
+
+        $captcha = Env::get('adminsystem.captcha', 1);
+        if ($this->request->isPost()) {
+            $post = $this->request->post();
+            $rule = [
+                'username|用户名' => 'require',
+                'password|密码' => 'require',
+                'keep_login|是否保持登录' => 'require',
+            ];
+            $captcha == 1 && $rule['captcha|验证码'] = 'require|captcha';
+            $this->validate($post, $rule);
+            $admin = SystemAdmin::where(['username' => $post['username']])->find();
+            if (empty($admin)) {
+                $this->error('用户不存在');
+            }
+            if (password($post['password']) != $admin->password) {
+                $this->error('密码输入有误');
+            }
+            if ($admin->status == 0) {
+                $this->error('账号已被禁用');
+            }
+            $admin->login_num += 1;
+            $admin->save();
+
+            Event::trigger('AdminLoginSuccess', $admin);
+
+            $admin = $admin->toArray();
+            unset($admin['password']);
+            $admin['expire_time'] = $post['keep_login'] == 1 ? true : time() + 7200;
+            session('admin', $admin);
+
+            $this->success('登录成功');
+        }
+        $this->assign('captcha', $captcha);
+        $this->assign('demo', $this->isDemo);
+
+        return $this->fetch();
+    }
+
+    /**
+     * 用户退出.
+     * @return mixed
+     */
+    public function out()
+    {
+        session('admin', null);
+        $this->success('退出登录成功');
+    }
+
+    /**
+     * 验证码
+     * @return \think\Response
+     */
+    public function captcha()
+    {
+        return Captcha::create();
+    }
+}