一、IoC方式
在Struts2中，所有請求都會被StrutsPrepareAndExecuteFilter攔截，然後去struts.xml尋找相印的action，在action執行前，會執行一些interceptor。在 struts-default.xml中，有個攔截器為
<interceptor name="servletConfig" class="org.apache.struts2.interceptor.ServletConfigInterceptor"/>
一部分原始碼

  public String intercept
 
(ActionInvocation invocation) throws Exception {
        final Object action = invocation.getAction();
        final ActionContext context = invocation.getInvocationContext();

        if (action instanceof ServletRequestAware) {
            HttpServletRequest request = (HttpServletRequest) context.get(HTTP_REQUEST);
            ((ServletRequestAware) action).setServletRequest(request);
        }

        if
 
 (action instanceof ServletResponseAware) {
            HttpServletResponse response = (HttpServletResponse) context.get(HTTP_RESPONSE);
            ((ServletResponseAware) action).setServletResponse(response);
        }
        if (action instanceof ServletContextAware) {
            ServletContext servletContext = (ServletContext) context.get(SERVLET_CONTEXT);
            ((ServletContextAware) action).setServletContext(servletContext);
        }
        return
 
 invocation.invoke();

於是我們可以通過IoC的方式，將Servlet物件注入Action中。

package action;
/**
 * @author ZZ
 * ****/
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;
import org.apache.struts2.util.ServletContextAware;

public class Struts2Action  implements ServletRequestAware,ServletResponseAware,ServletContextAware{

    @Override
    public void setServletContext(ServletContext context) {

    }

    @Override
    public void setServletResponse(HttpServletResponse response) {

    }

    @Override
    public void setServletRequest(HttpServletRequest request) {

    }


}

通過實現ServletRequestAware 獲得HttpServletRequest，
實現 ServletResponseAware 獲得HttpServletResponse,
實現 ServletContextAware來獲得HttpServletContext。
SessionAware之類的就不寫了。

二、非IoC方式
通過ServletActionContext的靜態方法獲取。

package action;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.ServletActionContext;

/**
 * @author ZZ
 * ****/

public class Struts2Action  {
    public void test(){
        HttpServletRequest request = ServletActionContext.getRequest();
        HttpServletResponse response = ServletActionContext.getResponse();
        ServletContext servletContext = ServletActionContext.getServletContext();
    }
}