Servlet之間通信的方式有兩大類，每個類有三種不同的方法

1.request

2.session

3.application

不實現ServletContextAware,SessionAware,ServletRequestAware這三個接口的通信

		HttpServletRequest request = ServletActionContext.getRequest();
		request.setAttribute("request_username", "username");
		HttpServletResponse response = ServletActionContext.getResponse();
		
		//這個是Servlet的session
//		HttpSession session = request.getSession();
//		session.setAttribute("session_username", "username");

		ServletContext servletContext = ServletActionContext.getServletContext();
		servletContext.setAttribute("application_username", "username");

實現ServletContextAware,SessionAware,ServletRequestAware這三個接口的通信

public class Servlet2Action extends ActionSupport implements
		ServletContextAware,SessionAware,ServletRequestAware {

	private HttpServletRequest request;
	private ServletContext servletContext;
	private Map<String,Object> sessionMap;

	/**
	 * {}struts2包裝以後的session,本質上是一個map
		[email protected] servlet中的application
		[email protected]  struts2包裝後的request
	 */
	public void setSession(Map<String, Object> arg0) {
		this.sessionMap=arg0;
		sessionMap.
	}
	public void setServletContext(ServletContext arg0) {
		this.servletContext=arg0;
	}
	
	public void setServletRequest(HttpServletRequest arg0) {
		this.request=arg0;
	}
	public String testServelet()
	{
		System.out.println(sessionMap.toString());
		System.out.println(servletContext.toString());
		System.out.println(request.toString());
		return "servelet";
	}

}

在目標頁面取出

   	request:${requestScope.request_username }<br>
   	session:${sessionScope.session_username }<br>
   	application:${applicationScope.application_username }<br>

struts2 servlet之間通信