PHP 简易MVC框架和容器的实现 - 课后作业

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1.MVC框架

分别建立模型类型、控制器类和视图类
在控制器中调用模型获取数据，然后调用视图类输出数据展示

1.1 Model类

该模型类功能主要是查询数据，所以直接继承Db数据库操作类

Model.php

<?php
namespace home;
require 'Db.php';
class Model extends Db
{
}

Db.php

<?php
namespace home;
//数据库操作类
class Db{
    public static $link = null;//保存pdo连接
    public static $sql = null;//保存语句
    //使用构造函数连接数据库
    public function __construct($dsn,$username,$password){
        try{
            self::$link = new \PDO($dsn,$username,$password);
            if(empty(self::$link)){
                echo '数据库连接失败';
            }
        }catch(\Exception $e){
            echo $e->getMessage();
        }
    }
    //新增数据
    public static function add(string $table,array $data){
        $val = array_values($data);
        $keys = array_map(function($item){
            return $item = '`'.$item.'`=?';
        },array_keys($data));
        $fields = implode(",",$keys);
        //预处理sql语句,使用占位符
        $sql = "insert {$table} set {$fields}";
        $stmt = self::$link->prepare($sql);
        //执行查询语句
        $stmt->execute($val);
        if($stmt->rowCount()===1){
            return self::$link->lastInsertId();//获取新增的主键ID
        }else{
            return $stmt->errorInfo();
        }
    }
    //查询数据
    public static function find(string $sql){
        //预处理sql语句
        $stmt = self::$link->prepare($sql);
        //执行查询语句
        $stmt->execute();
        return $stmt->fetchAll(\PDO::FETCH_ASSOC);
    }
    //更新数据
    public static function update(string $table,string $where,array $data)
    {
        $val = array_values($data);
        $keys = array_map(function($item){
            return $item = '`'.$item.'`=?';
        },array_keys($data));
        $fields = implode(",",$keys);
        //预处理sql语句,使用占位符
        self::$sql = "update `{$table}` SET  {$fields} {$where}";
        $stmt = self::$link->prepare(self::$sql);
        //执行查询语句
        $stmt->execute($val);
        if($stmt->rowCount()){
            return $stmt->rowCount();//返回受影响的记录数
        }else{
            return $stmt->errorInfo();
        }
    }
    //删除数据
    public static function delete($table,$where)
    {
        $sql = "DELETE FROM `{$table}` {$where}";
        self::$sql=$sql;
        $stmt = self::$link->prepare($sql);
        $stmt->execute();
        if($stmt->rowCount()){
            return $stmt->rowCount();//返回受影响的记录数
        }else{
            return $stmt->errorInfo();
        }
    }
}

1.2 View类

把数据在goods.php模板文件中展示

<?php
namespace home;
class View
{
    public function fetch($data){
        include 'goods.php';
    }
}

goods.php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>商品信息维护</title>
    <style>
    body {
        display: flex;
        flex-flow: column nowrap;
        align-items: center;
    }
    form {
        display: flex;
        flex-flow: row wrap;
    }
    form>section {
        margin: 10px;
        display: flex;
        flex-flow: row nowrap;
    }
    table {
        margin-top: 30px;
        width: 1000px;
        font-family: verdana, arial, sans-serif;
        font-size: 11px;
        color: #333333;
        border-width: 1px;
        border-color: #666666;
        border-collapse: collapse;
    }
    table>thead {
        background-color: #80ff80;
    }
    table th {
        border-width: 1px;
        padding: 8px;
        border-style: solid;
        border-color: #666666;
    }
    table td {
        border-width: 1px;
        padding: 8px;
        border-style: solid;
        border-color: #666666;
        background-color: #ffffff;
        text-align: center;
    }
    tfoot>tr,
    tfoot>tr>td {
        width: initial;
    }
    </style>
</head>
<body>
    <hr>
    <hr>
    <form action="<?php echo $_SERVER['PHP_SELF'] ?>" class="queryterms" method="POST">
        <section>
            <label for="goodsname">商品名称：</label>
            <input type="text" name="goodsname" id="goodsname"
                value="<?php if(isset($_SESSION['goodsname'])) echo $_SESSION['goodsname']?>">
        </section>
        <section>
            <label for="goodsmodel">商品型号：</label>
            <input type="text" name="goodsmodel" id="goodsmodel"
                value="<?php if(isset($_SESSION['goodsmodel'])) echo $_SESSION['goodsmodel']?>">
        </section>
        <section>
            <button>查询</button>
        </section>
    </form>
    <div>
        <table>
            <thead>
                <tr>
                    <th>ID</th>
                    <th>名称</th>
                    <th>型号</th>
                    <th>价格</th>
                    <th>数量</th>
                    <th>状态</th>
                    <th>操作</th>
                </tr>
            </thead>
            <tbody>
                <?php foreach($data as $val):?>
                <tr>
                    <td><?php echo $val['id'] ?></td>
                    <td><?php echo $val['name']?></td>
                    <td><?php echo $val['model']?></td>
                    <td><?php echo $val['price']?></td>
                    <td><?php echo $val['number']?></td>
                    <td><?php echo $val['status']?></td>
                    <td><a href="handle.php?act=edit&id=<?php echo $val['id'] ?>">编辑</a>
                        &nbsp;&nbsp;&nbsp;
                        <a href="handle.php?act=delete&id=<?php echo $val['id'] ?>">删除</a></td>
                </tr>
                <?php endforeach; ?>
            </tbody>
            <tfoot>
                <tr>
                    <td colspan="7"><?php if(isset($page))echo $page; ?></td>
                </tr>
            </tfoot>
        </table>
    </div>
</body>
</html>

1.3 Controller类

在Controller中实例化model和view类
然后调用find方法获取数据，调用fetch方法展示数据

<?php
namespace home;
require 'Model.php';
require 'View.php';
//.直接在方法内实例化外部类使用
class Controller
{
    public function index($dsn,$username,$password){
        $data = (new Model($dsn,$username,$password))::find('select * from goods limit 2');
        return (new View)->fetch($data);
    }
}
$ctrl = new Controller; 
$ctrl->index($dsn,$username,$password);

至此，就完成了一个最简单的mvc框架，Model类负责处理数据、view输出展示数据，controller类负责接收处理请求和返回数据

效果图：

2. 容器

以上mvc框架中的congtroller在类中直接实例化外部类，对外部类依赖性很强，代码耦合度高，如Model类的参数发生变化，congtroller类中也需要同步修改.
如Model类中重写构造方法为不传参，而是引入文件，以上的congtroller类就需要修改

<?php
namespace home;
require 'Db.php';
class Model extends Db
{
    public function __construct(){
        if(file_exists('config.php')){
            include 'config.php';
        }
        try{
            self::$link = new \PDO($dsn,$username,$password);
            if(empty(self::$link)){
                echo '数据库连接失败';
            }
        }catch(\Exception $e){
            echo $e->getMessage();
        }
    }
}

2.1 参数依赖

在此，我们可以通过参数方式传递外部类的实例来解耦

// 在参数中传入外部类的实例
class Controller
{
    public function index(Model $model,view $view){
        $data = $model::find('select * from goods limit 2,3');
        return $view->fetch($data);
    }
}
$ctrl = new Controller; 
$ctrl->index(new Model,new View);

效果图：

通过参数传递类实例的方式，成功把模型和视图类的实例创建放到了客户端，代码涉及改造量也大大降低。但是依赖的类很多时，要一个个的创建类的实例，也比较麻烦

2.2 服务容器

为解决以上问题，我们可以创建一个容器，把所有类的实例化步骤都放到该容器中，使用时直接用该类的别名即可获得该类的实例。
在容器类中有两个方法，一是绑定，将类在容器中注册服务；一是取出，根据注册的类的别名获取类的实例

服务容器：

<?php
namespace home;
//服务容器类
class Container
{
    public $binds = [];
    //绑定服务到容器
    public function bind($alias,\Closure $process){
        $this->binds[$alias] = $process; 
    }
    //使用
    public function make($alias,array $param=[]){ 
        return call_user_func_array($this->binds[$alias],$param); 
    }
}

容器依赖：

class Controller3
{
    public function index(Container $container){
        //从容器中取得model和view类的对象实例
        $data = $container->make('Model')::find('select * from goods limit 6,5');
        return $container->make('View')->fetch($data);
    }
}
$container = new Container;
//注册服务，绑定类到容器中
$container->bind('Model',function(){return new Model();});
$container->bind('View',function(){return new View;});
$container->bind('controller',function(){return new Controller3;});
//使用服务
$container->make('controller')->index($container);

效果图：

服务容器就像一个全局变量，把所有服务类放到容器中，使用时根据注册的名字即可直接获得实例

Correcting teacher：

天蓬老师

Correction status：qualified

Teacher's comments：理解了容器的概念, 写一个服务容器就简单了, 但是实际的服务容器, 比这个复杂多了,有对象, 有数组, 有闭包, 有函数, 有类, 有请求数据,甚至代码片断, 反射结果等, 但思想是不变的

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1.MVC框架

1.1 Model类

1.2 View类

1.3 Controller类

2. 容器

2.1 参数依赖

2.2 服务容器