YII的lazy loading
版本1 require('class\class1.php'); require('class\class1.php'); if($is_girl){ echo 'this is a girl'; $class1 = new Class1; }else{ echo "this is a boy"; $class2 = new Class2; } 版本2 if($is_girl){ echo 'this is a girl'; require('class\class1.php'); $class1 = new Class1; }else{ echo "this is a boy"; require('class\class1.php'); $class2 = new Class2; } 版本3 function my_loader($class){ require('class\class1.php'); require('class\class1.php'); } spl_auto_register('my_loader'); if($is_girl){ echo 'this is a girl'; $class1 = new Class1; }else{ echo "this is a boy"; $class2 = new Class2; } 版本4 function my_loader($class){ require('class\\'.$class.'.php'); } spl_auto_register('my_loader'); if($is_girl){ echo 'this is a girl'; $class1 = new Class1; }else{ echo "this is a boy"; $class2 = new Class2; } yii\wendor\yiisoft\yii2\yii.php