struts2 action中获取request session application的方法

共四种方式：

其中前两种得到的是Map<String,Object> 后两种得到的才是真正的request对象

而Map就是把request对象中的属性取出做成了键值对而已。

【方法一】

public class LoginAction {
    private Map request;
    private Map session;
    private Map application;
    
    public String execute() {
        request = (Map)ActionContext.getContext().get("request");
        session = ActionContext.getContext().getSession();
        application = ActionContext.getContext().getApplication();
        request.put("username1", "jingjing1");
        session.put("username2", "jingjing2");
        application.put("username3", "jingjing3");
        return "success";
    }
}

取出结果

 <body>
    <%
       String username1 = (String)request.getAttribute("username1");
       String username2 = (String)session.getAttribute("username2");
       String username3 = (String)application.getAttribute("username3");
    %>
    <%=username1 %>
    <%=username2 %>
    <%=username3 %>
  </body>

【方法二】

public class LoginAction implements RequestAware,SessionAware,ApplicationAware {
    private Map<String, Object> request;
    private Map<String, Object> session;
    private Map<String, Object> application;
    
    public void setRequest(Map<String, Object> request) {
        // TODO Auto-generated method stub
        this.request = request;
    }

    public void setSession(Map<String, Object> session) {
        // TODO Auto-generated method stub
        this.session = session;
    }

    public void setApplication(Map<String, Object> application) {
        // TODO Auto-generated method stub
        this.application = application;
    }
    public String execute() {
        request.put("username1", "jingjing11");
        session.put("username2", "jingjing222");
        application.put("username3", "jingjing33");
        return "success";
    }
}

【方法三】

public class LoginAction {
    private HttpServletRequest request;
    private HttpSession session;
    private ServletContext application;
    public String execute() {
            
        request = ServletActionContext.getRequest();
        session = request.getSession();
        application = session.getServletContext();
        
        //application = ServletActionContext.getRequest().getSession().getServletContext();
        
        request.setAttribute("aaa", "aaa");
        session.setAttribute("bbb", "bbb");
        application.setAttribute("ccc", "ccc");
        
        return "success";
    }
}

【方法四】

public class LoginAction implements ServletRequestAware {
    private HttpServletRequest request;
    private HttpSession session;
    private ServletContext application;
    
    public void setServletRequest(HttpServletRequest request) {
        // TODO Auto-generated method stub
        this.request = request;
        this.session = request.getSession();
        this.application = session.getServletContext();
    }
    
    public String execute() {        
        request.setAttribute("111", "111");
        session.setAttribute("222", "222");
        application.setAttribute("333", "333");
        return "success";
    }        
}

HttpServletRequest方法总结:

HttpServletRequest接口是继承自ServletRequest接口的，增加了和HTTP相关的一些方法

getScheme() 方法返回请求的计划，比如http,https或者ftp.
getServerName() 方法返回被发送请求的服务器的主机名
getServerPort() 方法返回被发送请求的端口号。
getContextPath() 返回请求地址的根目录，以"/"开关，但不是以"/"结尾。
一个常用的获得服务器地址的连接字符串是：
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

getCookies() 取得cookie
getMethod() 取得请求方法，如get,post或put
getRequestURL() 取得请求URL(统一资源定位符)
getRequestURI() 取得请求URI(统一资源标识符)
getSession() 取得对应session

public HttpSession getSession();
public HttpSession getSession(boolean create);
返回与这个请求关联的当前的有效的session。如果调用这个方法时没带参数，那么在没有session与这个请求关联的情况下，将会新建一个session。如果调用这个方法时带入了一个布尔型的参数，只有当这个参数为真时，session才会被建立。

ServletRequestAware与RequestAware的区别

ServletRequestAware——提供对HttpServletRequest对象的访问
RequestAware ——通过Map来提供对所有request属性的访问