Action类:

import java.io.UnsupportedEncodingException;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

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

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

/**
 * 获取Servlet API
 * @author 够潮
 *
 */
@SuppressWarnings("serial")
public class GetServletApiAction extends ActionSupport {

	
	/**
	 * 用户登录
	 */
	public void loginAction(){
		
		/**
		 * 获取Action上下文
		 */
		ActionContext ac = ActionContext.getContext();
		
		/**
		 * 获取Appication
		 */
		Map map  = ac.getApplication();
		/**
		 * 获取Session
		 */
		Map sessionMap = ac.getSession();
		
		/**
		 * 获取request
		 */
		HttpServletRequest request =  ServletActionContext.getRequest();
		
		
		/**
		 * 获取response
		 */
		HttpServletResponse response = ServletActionContext.getResponse();
		
		/**
		 * 获取前台传过来的参数
		 */
		String userName = request.getParameter("userName");
		String password = request.getParameter("password");
		try {
			/**
			 * 设置编码格式
			 */
			request.setCharacterEncoding("utf-8");
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		System.out.println("userName"+userName);
		System.out.println("password:"+password);
		
		
		ActionContext ac2 = ServletActionContext.getActionContext(request);
		System.out.println("ac2== ac --->"+(ac2==ac));
		System.out.println("sessionMap == map--->"+(sessionMap == ac2.getSession()));
	}
	
}

页面：

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>在Action中获取Servlet Api 专题</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
    <center>
    
     <h3>在Action中获取Servlet Api 专题</h3>
     <form action="servletApiAction!loginAction.action">
     
     userName:<input type="text" name="userName"><br>
     password:<input type="password" name="password"><br>
     <input type="submit" >
     
     </form>
    </center>
  </body>
</html>

配置文件：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>

	<package name="admin" namespace="/" extends="struts-default">
		
		
		<!-- ServletapiAction -->
        <action name="servletApiAction" class="action.GetServletApiAction">
        
        </action>
        

	</package>
</struts>