（一）Map（在web.xml中必须使用2.1以上的配置）

public class LoginAction1 extends ActionSupport {

private Map request;private Map session;private Map application;public LoginAction1() { request = (Map)ActionContext.getContext().get("request");session = ActionContext.getContext().getSession();application = ActionContext.getContext().getApplication();}public String execute() { request.put("r1", "r1");session.put("s1", "s1");application.put("a1", "a1");return SUCCESS; } }

（二）继承并实现RequestAware,SessionAware, ApplicationAware 接口（依赖注入，强烈推荐使用）

public class LoginAction2 extends ActionSupport implements RequestAware,SessionAware, ApplicationAware {

private Map<String, Object> request;private Map<String, Object> session;private Map<String, Object> application;//DI dependency injection//IoC inverse of controlpublic String execute() { request.put("r1", "r1");session.put("s1", "s1");application.put("a1", "a1");return SUCCESS; }@Overridepublic void setRequest(Map<String, Object> request) { this.request = request;}@Overridepublic void setSession(Map<String, Object> session) { this.session = session;}@Overridepublic void setApplication(Map<String, Object> application) { this.application = application;} }

（三）获得真实对象

public class LoginAction3 extends ActionSupport {

private HttpServletRequest request;private HttpSession session;private ServletContext application;public LoginAction3() { request = ServletActionContext.getRequest();session = request.getSession();application = session.getServletContext();}public String execute() { request.setAttribute("r1", "r1");session.setAttribute("s1", "s1");application.setAttribute("a1", "a1");return SUCCESS; } }

（四）依赖注入+获得真是对象

public class LoginAction4 extends ActionSupport implements ServletRequestAware {

private HttpServletRequest request;private HttpSession session;private ServletContext application;public String execute() { request.setAttribute("r1", "r1");session.setAttribute("s1", "s1");application.setAttribute("a1", "a1");return SUCCESS; }@Overridepublic void setServletRequest(HttpServletRequest request) { this.request = request;this.session = request.getSession();this.application = session.getServletContext();} }