struts2获取web元素(request、session、application)

一、Action中获取

第一种方式：

通过ActionContext,这种方式取到的对象是Map类型

import java.util.Map;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class UserAction extends ActionSupport{
    
    private String uid;
    
    public String login(){
        
        Map<String , Object> request = (Map<String, Object>) ActionContext.getContext().get("request");
        
        Map<String , Object> session = ActionContext.getContext().getSession();
        
        Map<String , Object> application = ActionContext.getContext().getApplication();
        
        if (uid != null) {
            
            System.out.println(uid);
            session.put("uid" , uid);
        }
        
        return SUCCESS;
    }
    
    public String getUid() {
        return uid;
    }

    public void setUid(String uid) {
        this.uid = uid;
    }
}

第二种方式：

通过实现RequestAware,SessionAware,ApplicationAware接口来获取,这种方式获取到的依然是Map类型

package cn.orlion.actions;

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.ActionSupport;

public class UserAction extends ActionSupport implements RequestAware,SessionAware,ApplicationAware{
    
    private String uid;
    
    private Map<String, Object> request;
    
    private Map<String, Object> session;
    
    private Map<String, Object> application;
    
    public String login(){
        
        if (uid != null) {
            
            System.out.println(uid);
            session.put("uid" , uid);
        }
        
        return SUCCESS;
    }
    
    public String getUid() {
        return uid;
    }

    public void setUid(String uid) {
        this.uid = uid;
    }

    @Override
    public void setSession(Map<String, Object> arg0) {
        // TODO Auto-generated method stub
        this.session = arg0;
    }

    @Override
    public void setRequest(Map<String, Object> arg0) {
        // TODO Auto-generated method stub
        this.request = arg0;
    }

    @Override
    public void setApplication(Map<String, Object> arg0) {
        // TODO Auto-generated method stub
        this.application = arg0;
    }
}

第三种方式：

通过实现ServletRequestAware接口获取到request,然后用request去获取session和application,这种方式获取到的是HttpServletRequest ,HttpSession ,ServletContext类型。

package cn.orlion.actions;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import org.apache.struts2.interceptor.ServletRequestAware;

import com.opensymphony.xwork2.ActionSupport;

public class UserAction extends ActionSupport implements ServletRequestAware{
    
    private String uid;
    
    private HttpServletRequest request;
    
    private HttpSession session;
    
    private ServletContext application;
    
    public String login(){
        
        if (uid != null) {
            
            session = request.getSession();
            
            application = session.getServletContext();
            
            System.out.println(uid);
　　　　　　　// HttpSession类型，所以用setAttribute方法
            session.setAttribute("uid" , uid);
        }
        
        return SUCCESS;
    }
    
    public String getUid() {
        
        return uid;
    }

    public void setUid(String uid) {
        this.uid = uid;
    }

    @Override
    public void setServletRequest(HttpServletRequest arg0) {
        // TODO Auto-generated method stub
        this.request = arg0;
    }
}

第四种方式：

用ServletActionContext得到request再得到sesion和application，这种获取到的类型与第二种相同

package cn.orlion.actions;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class UserAction extends ActionSupport{
    
    private String uid;
    
    private HttpServletRequest request;
    
    private HttpSession session;
    
    private ServletContext application;
    
    public String login(){
        
        if (uid != null) {
            
            request = ServletActionContext.getRequest();
            
            session = request.getSession();
            
            application = session.getServletContext();
            
            System.out.println(uid);
            session.setAttribute("uid" , uid);
        }
        
        return SUCCESS;
    }
    
    public String getUid() {
        
        return uid;
    }

    public void setUid(String uid) {
        this.uid = uid;
    }
}

二、JSP中获取

通过session.setAttribute()方式设置的值不能通过<s:property value="#session.uid" />方式获取到。

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>success</title>
</head>
<body>
    uid为:<s:property value="#session.uid" />|||<br/>
       ${ sessionScope.uid }
       
       <s:debug></s:debug>
</body>
</html>