Zend 1不使用psr-4命名空间

I am working on zend framework 1 But I want to use \ instead of _

Like

class IndexController extends Zend_Controller_Action 

This is working fine but when I changed this by

class IndexController extends \Zend\Controller\Action

Then its giving me a error

Fatal error: Cannot redeclare class Zend_Controller_Action in /var/www/flipit_application/vendor/zendframework/zendframework1/library/Zend/Controller/Action.php on line 43

I have created the namespaces in composer

"autoload": {
        "psr-4": {
            "Zend\\": "vendor/zendframework/zendframework1/library/Zend/"
        }
    },

So how Can use these namespaces in code

Is this possible in Zend Framework1?.

Zend Framework 1 doesn't use psr-4 autoloading, it uses psr-0:

"autoload": {
    "psr-0": {
        "Zend_": "vendor/zendframework/zendframework1/library"
    }
}