如何防止调用不存在的方法而出错,使用__call魔术重载方法.
__call方法原型如下:
mixed __call(string $name,array $arguments)
当调用一个不可访问的方法(如未定义,或者不可见时), __call()就会被调用.其中$name参数是要调用的方法名称.$arguments参数是一个数组,包含者要传递给方法的参数,
如下所示:
<?phpclass HandsonBoy{ ???private $name = ‘chenqionghe‘; ???private $age = 18; ???public function __call($name,$arguments) ???{ ???????switch(count($arguments)) ???????{ ???????????case 2: ???????????????echo $arguments[0] * $arguments[1],PHP_EOL; ???????????????break; ???????????case 3: ???????????????echo array_sum($arguments),PHP_EOL; ???????????????break; ???????????default: ???????????????echo ‘参数不对‘,PHP_EOL; ???????????????break; ???????} ???}}$a = new HandsonBoy();$a->make(5);$a->make(5,6);以上代码模拟了类似其他语言中的根据参数类型进行重载.跟__call配套的魔方方法是__callStatic.
当然,使用魔术方法"防止调用不存在的方法面报错",并不是魔术方法的本质.实际上,魔术方法使用方法的动态创建变为可能.这在MVC等框架设计中是很有用的语法.假设一个控制器调用了不存在的方法,那么只要定义了__call魔术方法,就能很友好地处理这种情况.
以下代码通过使用_callStatic这一魔术方法进行方法的动态创建和延迟绑定,实现一个简单的ORM模型
<?phpabstract class ActiveRecord{ ???protected static $table; ???protected $fieldvalue; ???public $select; ???static function findById($id) ???{ ???????$query = "SELECT * FROM " . static::$table . " WHERE id=$id"; ???????return self::createDomain($query); ???} ???function __get($fieldname) ???{ ???????return $this->fieldvalues[$fieldname]; ???} ???static function __callStatic($method,$args) ???{ ???????$field = preg_replace(‘/^findBy(\w*)$/‘, ‘$1‘ , $method); ???????$query = "SELECT * FROM " . static::$table . " WHERE $field=‘$args[0]‘"; ???????return self::createDomain($query); ???} ???private static function createDomain($query) ???{ ???????$class = get_called_class();//获取静态方法调用的类名 ???????$domain = new $class(); ???????$domain->fieldvalues = array(); ???????$domain->select = $query; ???????foreach ($class::$fields as $field => $type) ???????{ ???????????$domain->fieldvalues[$field] = ‘TODO:set from sql result by ‘ . $field; ???????} ???????return $domain; ???}}class Customer extends ActiveRecord{ ???protected static $table = ‘custdb‘; ???protected static $fields = array( ???????‘id‘ => ‘int‘, ???????‘email‘ => ‘int‘, ???????‘lastname‘ => ‘varchar‘ ???);}class Sales extends ActiveRecord{ ???protected static $table = ‘salesdb‘; ???protected static $fields = array( ???????‘id‘ => ‘int‘, ???????‘item‘ => ‘varchar‘, ???????‘qty‘ => ‘int‘ ???);}var_dump(Customer::findById(123)->select);var_dump(Customer::findById(123)->email);var_dump(Sales::findByLastname(‘Denoncourt‘)->select);参考：https://jingyan.baidu.com/article/48a42057fd2890a92425043c.html
转：https://www.cnblogs.com/chenqionghe/p/4735703.html?tvd
参考：http://www.php.net/manual/zh/language.oop5.magic.php
PHP中的__call和__callStatic方法（未看完）
原文地址：http://www.cnblogs.com/fps2tao/p/8030156.html