struts 2 里session传值的问题

Question

为什么在JSP页面接收SESSION的值总是NULL呢
LoginAction.java
public class LoginAction extends ActionSupport{//这个类继承了ActionSupport类，
private String userid;

private String password;

public String getUserid() {   
    return userid;   
}   

public void setUserid(String userid) {   
    this.userid = userid;   
}   

public String getPassword() {   
    return password;   
}   

public void setPassword(String password) {   
    this.password = password;   
}   

public String execute(HttpServletRequest request) throws Exception {   
    RegisterDAO dao = new RegisterDAO();
       List<User> userlist1 = dao.allUsers();
       for(int i=0;i<userlist1.size();i++){
       if (userlist1.get(i).getUserid().equals(this.userid)&&userlist1.get(i).getPassword().equals(this.password)){
           request.getSession().setAttribute("id", this.userid); 
           return "success";
       }
       }
           return "fail";

}   

}

struts.xml



/success.jsp
/error.jsp

主页面jsp

<%
String b=(String)session.getAttribute("id");
out.print(b);
%>

结果显示null

Answer 1

public String execute(HttpServletRequest request) throws Exception {

RegisterDAO dao = new RegisterDAO();
List userlist1 = dao.allUsers();
for(int i=0;i<userlist1.size();i++){
if (userlist1.get(i).getUserid().equals(this.userid)&&userlist1.get(i).getPassword().equals(this.password)){
request.getSession().setAttribute("id", this.userid);
return "success";
}
}
return "fail";

}   

actionContext.getcontext.getSession().put("dd","dd");

struts2中对用户请求进行处里时struts2自动创建一个request，对象，而不是给传值。