在Action中获取servlet API（1）

Struts2的Action组件是不依赖servlet API 的。那么当你在action中的业务需要处理HttpServletRequest和HttpServletResponse的时候（比如要对响应做处理写cookie，生成验证码）怎么办呢?

有3种办法可以实现action中获取servlet api

1.使用ServletActionContext的静态方法

Struts2使用ServletActionContext对象维护Servlet api 对象（像request,response,session,application）。ServletActionContext使用ThreadLocal(线程局部变量，关于ThreadLocal请参看本博另一篇文章《理解TheadLocal（线程局部变量）》),这样能保证获取的是当前用户当前线程的servlet api对象。

public class TestAction {HttpServletRequest request = ServletActionContext.getRequest();HttpServletResponse response = ServletActionContext.getResponse();HttpSession session =  request.getSession();ActionContext actionContext = ServletActionContext.getActionContext(request);ActionContext context = ServletActionContext.getContext();ActionMapping mapping = ServletActionContext.getActionMapping();PageContext pageContext =  ServletActionContext.getPageContext();ServletContext servletContext = ServletActionContext.getServletContext();ValueStack valueStack = ServletActionContext.getValueStack(request);}

2.使用ActionContext

public class TestAction {    ActionContext context = ActionContext.getContext();        public void test(){ActionInvocation actionInvocation = context.getActionInvocation();Locale locale = context.getLocale();ValueStack valueStack = context.getValueStack();Container container =  context.getContainer();Map<String, Object> parameters = context.getParameters();Map<String, Object> session = context.getSession();Map<String, Object> application = context.getApplication();Map<String, Object> contextMpap = context.getContextMap();Map<String, Object> conversionErrorss = context.getConversionErrors();    }    }

3.使用Struts2的资源注入拦截器

让你的action继承几个接口，实现他们的方法，然后声明serlvet api对象的变量就行了，在运行时struts2会把相对的对象注入到你的变量中。

这种注入不用多解释肯定是拦截器实现的啦！

而且值得注意的是session的接收变量是一个map而不是httpsession

public class TestAction implements ServletContextAware,ServletRequestAware,ServletResponseAware,SessionAware {private ServletContext servletContext;private HttpServletRequest request;private HttpServletResponse response;private Map<String, Object> session;/***实现相应接口的方法******/public void setServletContext(ServletContext arg0) {this.servletContext  = arg0;}public void setServletRequest(HttpServletRequest arg0) {This.request = arg0;}public void setServletResponse(HttpServletResponse arg0) {This.response = arg0;}public void setSession(Map<String, Object> arg0) {This.sessoin = arg0;}}