从我的插件中调用Woocommerce插件的功能

I am new to wordpress, trying to develop a wordpress plugin where I need to call a woocommerce method add_to_cart from the class woocommerce/includes/class-wc-cart.php. Is there any way to do that ?

WooCommerce declares a handy globlal WC() that you can use inside your plugin to call its functions.

Add the following code to your plugin

add_action('woocommerce_after_single_product', 'woo_foo');

function woo_foo() {        
    WC()->cart->add_to_cart( 254, 1 ); //ensure to change 254 with product ID on your system.               
}

Above code will automatically add a product to the cart when you visit the single product page. Here's a list of hooks & filters offered by WooCommerce that you can hook into.