[TOC] # 原理  Struts2框架在運行時，請求會被StrutsPrepareAndExecuteFilter攔截，會根據請求，去 strtus.xml文件中查找到匹配的action，在action執行前，會走一些interceptor 默認執行的攔截器是struts-default.xml文件中定義的。 在默認執行的攔截器中有一個  查看一下ServletConfigInterceptor源代碼 以下是部分源代碼  ServletRequestAware, 實現這個接口可以獲取HttpServletRequest ServletResponseAware ,實現這個接口可以獲取HttpServletResponse ServletContextAware 實現這個接口可以獲取ServletContext # 通過ActionContext 推薦 ~~~ // request域 => map (struts2并不推薦使用原生request域) // 不推薦 //import java.util.Map; Map<String, Object> requestScope = (Map<String, Object>) ActionContext.getContext().get("request"); // 推薦 ActionContext.getContext().put("name", "requestTom"); // session域 => map Map<String, Object> sessionScope = ActionContext.getContext().getSession(); sessionScope.put("name", "sessionTom"); // application域=>map Map<String, Object> applicationScope = ActionContext.getContext().getApplication(); applicationScope.put("name", "applicationTom"); System.out.println(ActionContext.getContext().get("name")); System.out.println(sessionScope.get("name")); System.out.println(applicationScope.get("name")); ~~~ # 通過ServletContext 不推薦 ~~~ // import javax.servlet.ServletContext; // import javax.servlet.http.HttpServletRequest; // import javax.servlet.http.HttpServletResponse; // import javax.servlet.http.HttpSession; // 不推薦 // 原生request HttpServletRequest request = ServletActionContext.getRequest(); // 原生session HttpSession session = request.getSession(); // 原生response HttpServletResponse response = ServletActionContext.getResponse(); // 原生ServletContext ServletContext servletContext = ServletActionContext.getServletContext(); ~~~ # 通過實現接口方式 想要什么就實現什么接口,ServletXXXXXAware ~~~ package domain; import javax.servlet.http.HttpServletRequest; import org.apache.struts2.interceptor.ServletRequestAware; public class HelloAction implements ServletRequestAware { private HttpServletRequest request; public String hello() { System.out.println("原生request: " + request); return "success"; } @Override public void setServletRequest(HttpServletRequest arg0) { // TODO Auto-generated method stub this.request = arg0; } } ~~~