如何在Struts with Tiles中获取真实的请求URL？

import javax.servlet.http.HttpServletRequest;

public class MyAction extends ActionSupport {
    private HttpServletRequest request;

    public void setRequest(HttpServletRequest request) {
        this.request = request;
    }

    public String execute() {
        StringBuffer requestURL = request.getRequestURL();
        // 使用requestURL进行后续操作
        return SUCCESS;
    }
}

<!-- Struts配置文件 --><action name="myAction" class="com.example.MyAction">
   <result name="success">/myPage.jsp</result>
</action>

<!-- Tiles配置文件 --><definition name="myPage" extends="baseLayout">
    <put-attribute name="title" value="My Page" />
    <put-attribute name="requestURL" expression="${request.requestURL}" />
</definition>

<!-- JSP视图层 -->
<tiles:insertAttribute name="requestURL" />