准备工作：
1、下载laravel框架
2、配置好项目（数据库连接以及虚拟主机）

开始：
前台用户认证laravel已经为我们写好了，此部分可参考官方文档

创建模型（以adminstrator为例）

php artisan make:model Models/Adminstrator -m

编写administrator表迁移

Schema::create('administrators', function (Blueprint $table) {$table->engine = 'InnoDB';$table->increments('id');$table->string('login_name')->unique();$table->string('display_name')->nullable();$table->string('password');$table->string('avatar')->nullable();$table->rememberToken();$table->tinyInteger('status')->default(1);$table->timestamps();
});

编写administrator模型

<?phpnamespace App\Models;use Illuminate\Auth\Authenticatable;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Contracts\Auth\Authenticatable as AuthenticatableContract;class Administrator extends Model implements AuthenticatableContract
{use Authenticatable;protected $fillable = ['login_name', 'password'];protected $hidden = ['password', 'remember_token'];
}

创建后台配置文件admin.php，在return数组中写入

'auth' => ['guards' => ['administrator' => ['driver'   => 'session','provider' => 'administrators',],],'providers' => ['administrators' => ['driver' => 'eloquent','model'  => \App\Models\Administrator::class,],],
],

创建后台用户认证中间件Authenticate，运行：

php artisan make:middleware Admin/Authenticate

修改handle方法：

<?php/*** 用户认证中间件*/namespace App\Http\Middleware\Admin;use Closure;
use Illuminate\Support\Facades\Auth;class Authenticate
{/*** Handle an incoming request.** @param  \Illuminate\Http\Request  $request* @param  \Closure  $next* @return mixed*/public function handle($request, Closure $next){if (Auth::guard('administrator')->guest() && !$this->shouldPassThrough($request)) {return redirect()->guest(admin_base_path('login'));}return $next($request);}/*** Determine if the request has a URI that should pass through verification.** @param \Illuminate\Http\Request $request** @return bool*/protected function shouldPassThrough($request){$excepts = [admin_base_path('login'),admin_base_path('logout'),];foreach ($excepts as $except) {if ($except !== '/') {$except = trim($except, '/');}if ($request->is($except)) {return true;}}return false;}
}

创建AdminServiceProvider，运行：

php artisan make:provider AdminServiceProvider

编写：

<?phpnamespace App\Providers;use Illuminate\Support\ServiceProvider;class AdminServiceProvider extends ServiceProvider
{/*** 路由中间件* @var array*/protected $routeMiddleware = ['admin.auth' => \App\Http\Middleware\Admin\Authenticate::class,'admin.pjax' => \Spatie\Pjax\Middleware\FilterIfPjax::class,'admin.log' => \App\Http\Middleware\Admin\LogOperation::class,];/*** 中间件组* @var array*/protected $middlewareGroups = ['admin' => ['admin.auth','admin.pjax','admin.log',],];/*** Bootstrap services.** @return void*/public function boot(){if (file_exists($routes = base_path('routes/admin.php'))) {$this->loadRoutesFrom($routes);}}/*** Register services.** @return void*/public function register(){$this->loadAdminAuthConfig();$this->registerRouteMiddleWare();}/*** 注册路由中间件*/public function registerRouteMiddleWare(){// 注册路由中间件foreach ($this->routeMiddleware as $key => $middleware) {app('router')->aliasMiddleware($key, $middleware);}// 注册路由中间件组foreach ($this->middlewareGroups as $key => $middleware) {app('router')->middlewareGroup($key, $middleware);}}/*** Setup auth configuration.** @return void*/protected function loadAdminAuthConfig(){config(array_dot(config('admin.auth', []), 'auth.'));}
}

在config/app.php中注册provider和facades

'providers' => [...,App\Providers\AdminServiceProvider::class,
]'aliases' => [...,'Admin' => App\Facades\Admin\Admin::class,
]

创建登录表单验证类，运行：

php artisan make:request AdministratorLoginRequest

重写其父类rules及messages方法：

<?phpnamespace App\Http\Requests;use Illuminate\Foundation\Http\FormRequest;class AdministratorLoginRequest extends FormRequest
{/*** Determine if the user is authorized to make this request.** @return bool*/public function authorize(){return true;}/*** Get the validation rules that apply to the request.** @return array*/public function rules(){return ['login_name' => 'required','password' => ['required', 'min:6'] //密码必须，最小长度为6];}public function messages(){return ['login_name.required' => '请输入用户名','password.required' => '请输入密码','password.min' => '密码至少6位',];}
}

创建登录控制器，运行：

php artisan make:controller Admin/Auth/LoginController

编写登录方法：

<?phpnamespace App\Http\Controllers\Admin\Auth;use App\Http\Requests\AdministratorLoginRequest;
use Illuminate\Http\Request;
use App\Http\Controllers\Controller;
use Illuminate\Support\Facades\Auth;class LoginController extends Controller
{/*** 登录表单* @return \Illuminate\Contracts\View\Factory|\Illuminate\View\View*/public function getLoginForm(){if (!Auth::guard('administrator')->guest()) {return redirect(config('admin.route.prefix'));}return view(admin_view_base_path('auth.login.index'));}/*** 登录操作* @param AdministratorLoginRequest $loginRequest* @return \Illuminate\Http\RedirectResponse|\Illuminate\Routing\Redirector*/public function postLogin(AdministratorLoginRequest $loginRequest){$postData = $loginRequest->only('login_name', 'password', 'remember');$result = Auth::guard('administrator')->attempt($postData, $loginRequest->filled('remember'));if ($result) {admin_toast('登录成功');$loginRequest->session()->regenerate();return redirect()->intended(config('admin.route.prefix'));}else{return redirect()->back()->withInput()->withErrors(['login_name' => '用户名或密码错误']);}}/*** 注销登录* @return \Illuminate\Http\RedirectResponse|\Illuminate\Routing\Redirector*/public function postLogout(){Auth::guard('administrator')->logout();session()->forget('url.intented');return redirect(config('admin.route.prefix'));}
}

至此，认证业务已经完成，接下来进行完善，使系统能够跑起来

创建视图文件（ps：1、控制器中使用的admin_view_base_path为自定义函数，指向后台视图文件主目录。2、视图采用AdminLTE框架）
login.blade:form

<form action="{{ admin_base_path('login') }}" method="post">@csrf<div class="form-group has-feedback"><input type="text" class="form-control {{ $errors->has('login_name') ? ' is-invalid' : '' }}"placeholder="登 录 名" name="login_name" value="{{ old('login_name') }}" required autofocus><span class="glyphicon glyphicon-envelope form-control-feedback"></span>@if ($errors->has('login_name'))<span class="invalid-feedback"><strong class="text-danger">{{ $errors->first('login_name') }}</strong></span>@endif</div><div class="form-group has-feedback"><input type="password" class="form-control {{ $errors->has('password') ? ' is-invalid' : '' }}"placeholder="密 码" name="password" required><span class="glyphicon glyphicon-lock form-control-feedback"></span>@if ($errors->has('password'))<span class="invalid-feedback"><strong class="text-danger">{{ $errors->first('password') }}</strong></span>@endif</div><div class="row"><div class="col-xs-8"><div class="checkbox icheck"><label><input type="checkbox" name="remember" {{ old('remember') ? 'checked' : '' }}> 记住我</label></div></div><!-- /.col --><div class="col-xs-4"><button type="submit" class="btn btn-primary btn-block btn-flat">登 录</button></div><!-- /.col --></div></form>

创建后台home控制器，运行：

php artisan make:controller Admin/Home/HomeController

编写index方法返回视图

<?phpnamespace App\Http\Controllers\Admin\Home;use Illuminate\Http\Request;
use App\Http\Controllers\Controller;class HomeController extends Controller
{//public function index(){return view(admin_view_base_path('home.index'));}}

若仅作登录之后跳转测试，home视图中保留注销按钮即可，例：
home.blade

<div class="pull-right"><a class="btn btn-default btn-flat" href="/admin/logout"onclick="event.preventDefault();document.getElementById('logout-form').submit();">{{ __('注 销') }}</a>
</div><form id="logout-form" class="hide" action="{{ admin_base_path('logout') }}" method="POST" style="display: none;">@csrf
</form>

编辑配置文件config.admin.php,加入以下配置：

'route' => ['prefix' => 'admin','namespace' => 'App\\Http\\Controllers\\Admin','middleware' => ['web', 'admin'],
],

编写路由文件routes/admin.php

<?phpuse Illuminate\Routing\RouterRoute::group(['prefix'        => config('admin.route.prefix'),'namespace'     => config('admin.route.namespace'),'middleware'    => config('admin.route.middleware'),
], function (Router $router) {$router->get('/', 'Home\HomeController@index');$router->get('login', 'Auth\LoginController@getLoginForm');$router->post('login', 'Auth\LoginController@postLogin');$router->post('logout', 'Auth\LoginController@postLogout');
});

数据表迁移与填充: 修改database/seeds/DatabaseSeeder

<?phpuse Illuminate\Database\Seeder;class DatabaseSeeder extends Seeder
{/*** Seed the application's database.** @return void*/public function run(){// $this->call(UsersTableSeeder::class);DB::table('administrators')->insert(['login_name' => 'admin','display_name' => '超级管理员','password' => bcrypt('123456'),'created_at' => date('Y-m-d H:i:s', time()),'updated_at' => date('Y-m-d H:i:s', time()),]);}
}

运行：

php artisan migrate //数据表迁移
php artisan db:seed //数据填充

如果前台使用了laravel框架用户认证的话，需要重写框架生成的LoginController的logout方法。防止前台用户注销的时候清除后台用户的session。（ps:框架自带用户认证在注销时会清空所有session）

/*** 重写前台注销操作* @param Request $request* @return \Illuminate\Http\RedirectResponse|\Illuminate\Routing\Redirector*/
public function logout(Request $request)
{$this->guard()->logout();$request->session()->forget('uri.intented');return redirect('/');
}

至此，后台用户登录全部完成。enjoy it！