How to obtain request, session, and application in Struts2

There are four methods
First:
Obtain the request, session, and application of the MAP type.
Write in a java File

package com.xjtu.st;import java.util.Map;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;public class LoginAction extends ActionSupport{private Map request;private Map session;private Map application;public LoginAction(){request = (Map)ActionContext.getContext().get("request");session = ActionContext.getContext().getSession();application = ActionContext.getContext().getApplication();}public String execute(){request.put("rs", "rs");session.put("ss", "ss");application.put("as", "as");return SUCCESS;}}

ActionContext. getContext () is to obtain the context of the Action, and then obtain the request of the MAP type.
Parameters are available on the output page.

<% @ Page language = "java" import = "java. util. * "pageEncoding =" GBK "%> <% @ taglib uri ="/struts-tags "prefix =" s "%> <% String path = request. getContextPath (); String basePath = request. getScheme () + ": //" + request. getServerName () + ":" + request. getServerPort () + path + "/"; %>              My JSP 'myjsp. jsp 'starting page    
 
 
     
 
 
       Hello
 
  

    
  
   
  
<% = Request. getAttribute ("rs") %>

 <% = Session. getAttribute ("ss") %>
<% = Application. getAttribute ("as") %>
     

Second:
Implement the RequestAware, SessionAware, and ApplicationAware interfaces. This method can be DI (dependency injection) or IOC (control inversion ). The Code is as follows:

package com.xjtu.st;import java.util.Map;import org.apache.struts2.interceptor.ApplicationAware;import org.apache.struts2.interceptor.RequestAware;import org.apache.struts2.interceptor.SessionAware;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;public class LoginAction extends ActionSupport implements RequestAware,SessionAware,ApplicationAware{private Map request;private Map session;private Map application;public String execute(){request.put("rs", "rrs");session.put("ss", "sss");application.put("as", "aas");return SUCCESS;}public void setRequest(Map
 
   request) {// TODO Auto-generated method stubthis.request=request;}public void setSession(Map
  
    session) {// TODO Auto-generated method stubthis.session= session;}public void setApplication(Map
   
     application) {// TODO Auto-generated method stubthis.application = application;}}
   
  
 

The first two types are Map types, and the last two are HtteServletRequest, HttpSession, and ServletContext types. The third is:
The Code is as follows:

package com.xjtu.st;import java.util.Map;import javax.servlet.ServletContext;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpSession;import org.apache.struts2.ServletActionContext;import org.apache.struts2.interceptor.ApplicationAware;import org.apache.struts2.interceptor.RequestAware;import org.apache.struts2.interceptor.SessionAware;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;public class LoginAction extends ActionSupport {private HttpServletRequest request;private HttpSession session;private ServletContext application;public LoginAction(){request= ServletActionContext.getRequest();session = request.getSession();application = session.getServletContext();}public String execute(){request.setAttribute("rs", "rrrs");session.setAttribute("ss", "ssss");application.setAttribute("as", "aaas");return SUCCESS;}}

This method is not commonly used:
It is also an ioc method.
The Code is as follows:

package com.xjtu.st;import java.util.Map;import javax.servlet.ServletContext;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpSession;import org.apache.struts2.ServletActionContext;import org.apache.struts2.interceptor.ApplicationAware;import org.apache.struts2.interceptor.RequestAware;import org.apache.struts2.interceptor.ServletRequestAware;import org.apache.struts2.interceptor.SessionAware;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;public class LoginAction extends ActionSupport implements ServletRequestAware{private HttpServletRequest request;private HttpSession session;private ServletContext application;public String execute(){request.setAttribute("rs", "rrrrs");session.setAttribute("ss", "sssss");application.setAttribute("as", "aaaas");return SUCCESS;}public void setServletRequest(HttpServletRequest request) {// TODO Auto-generated method stubthis.request = request;session = request.getSession();application = session.getServletContext();}}