在Action中获取servlet API 羽毛

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();
    }

}