如何在我的操作中获取 ServletRequest 实例？

我实现了 ServletRequestAware 但我无法在操作中获取请求对象。

struts.xml

<package name="default" extends="struts-default,json-default"> 
    <action name="Cart" 
    class="struts.cart.action.CartAction"> 
        <interceptor-ref name="json"> 
            <param name="contentType">application/json</param> 
        </interceptor-ref> 
        <result type="json"/>  
    </action>    
</package> 

我正在使用 Ajax/JavaScript 进行调用:

req.onreadystatechange = onReadyState;   
req.open(POST, Cart.action, false);   
req.setRequestHeader("Content-Type", "application/json; charset=utf-8");   
req.send(JSONstr); 

JSON 对象:

var data = { cartItem: { 
     modelNo: $('#modelNo').val(), 
     description: $('#description').val(), 
     price: $('#price').val(), 
     action: $('#action').val(), 
     quantity: $('#quantity').val() 
}}; 
JSONstr = JSON.stringify(data); 

行动:

public class CartAction extends ActionSupport implements  ServletRequestAware { 
 
    private HttpServletRequest request; 
    private Map cartItem = new HashMap(); 
 
    public String execute() throws Exception { 
        System.out.println("request  " + cartItem); // getting here cartitem 
        System.out.println("request  " + request);  // request  null  
    } 
 
    public void setServletRequest(HttpServletRequest httpServletRequest) { 
        this.request = httpServletRequest; 
    } 
 
    public Map getCartItem() { 
        return cartItem; 
    } 
 
    public void setCartItem(Map cartItem) { 
        this.cartItem = cartItem; 
    } 
 
}    

请您参考如下方法:

试试这个

HttpServletRequest request = ServletActionContext.getRequest() ;