struts2 Action 访问web对象（request，session,application）

Struts2 Action 访问web对象一共有四种，分别是：

一、创建request，session，application的Map对象

二、实现RequestAware,SessionAware,ApplicationAware接口(IOC注入)

三、创建传统的HttpServletRequest,HttpSession,ServletContext对象

四、实现ServletRequestAware，ServletContextAware接口(IOC注入)

其中 二、四方法是ICO（注入）方式实现，都是通过一、二的基础上加以改进的实现方式，下面列举相对应的集体实例：

一、创建request，session，application的Map对象(主要代码背景蓝色标记)

LoginAction.java

package com.wym.action;

import java.util.Map;

import com.opensymphony.xwork2.ActionContext;

import com.opensymphony.xwork2.ActionSupport;

import com.wym.bean.User;

import com.wym.bussiess.UserDao;

public class LoginAction extends ActionSupport{

private User user;

private Map<String, Object> request;

private Map<String, Object> session;

private Map<String, Object> application;

public LoginAction(){

System.out.println("执行LoginAction构造方法！");

request = (Map)ActionContext.getContext().get("request");

session = ActionContext.getContext().getSession();

application = ActionContext.getContext().getApplication();

}

public String execute(){

UserDao userDao = new UserDao();

if(userDao.loginUser(user)){

request.put("a", "this is a");

session.put("b", "this is b");

application.put("c", "this is c");

return "success";

}

else{

return "faint";

}

}

public User getUser() {

return user;

}

public void setUser(User user) {

this.user = user;

}

}

获取web对象的值（jsp文件中）

<s:property value="#request.a"/><br/> //获取request域中的值

<s:property value="#session.b"/><br/> //获取session域中的值

<s:property value="#application.c"/><br/>

<s:property value="#attr.b"/><br/> //先发现那个域由该属性名就使用该域

从实例中可以看到，该方式的实现方法，首先创建私有（private）的Map对象，

对象名分别为request、session、application 之后在Action的构造方法中初始化这三个Map对象，在为这三个对象赋值时，要使用Map的put方法。

二、实现RequestAware,SessionAware,ApplicationAware接口

该方式与第一种方式差不多，仅仅是实现RequestAware，SessionAware，ApplicationAware三个接口 并实现对应的方法 也需要创建Map对象 但不需要再Action的构造方法中初始化

package com.wym.action;

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;

import com.wym.bean.User;

import com.wym.bussiess.UserDao;

public class LoginAction extends ActionSupport implements RequestAware, SessionAware, ApplicationAware{

private User user;

private Map<String, Object> request;

private Map<String, Object> session;

private Map<String, Object> application;

public LoginAction(){

System.out.println("执行LoginAction构造方法！");

}

public String execute(){

UserDao userDao = new UserDao();

if(userDao.loginUser(user)){

request.put("a", "this is a");

session.put("b", "this is b");

application.put("c", "this is c");

return "success";

}

else{

return "faint";

}

}

public User getUser() {

return user;

}

public void setUser(User user) {

this.user = user;

}

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;

}

}

三、创建传统的HttpServletRequest,HttpSession,ServletContext对象

package com.wym.action;

import javax.servlet.ServletContext;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

import com.wym.bean.User;

import com.wym.bussiess.UserDao;

public class LoginAction extends ActionSupport{

private User user;

private HttpServletRequest request;

private HttpSession session;

private ServletContext application;

public LoginAction(){

System.out.println("执行LoginAction构造方法！");

request = ServletActionContext.getRequest();

session = request.getSession();

application = session.getServletContext();

}

public String execute(){

UserDao userDao = new UserDao();

if(userDao.loginUser(user)){

request.setAttribute("a", "this is a");

session.setAttribute("b", "this is b");

application.setAttribute("c", "this is c");

return "success";

}

else{

return "faint";

}

}

public User getUser() {

return user;

}

public void setUser(User user) {

this.user = user;

}

}

四、实现ServletRequestAware，ServletContextAware接口

package com.wym.action;

import javax.servlet.ServletContext;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;

import org.apache.struts2.interceptor.ServletRequestAware;

import org.apache.struts2.util.ServletContextAware;

import com.opensymphony.xwork2.ActionSupport;

import com.wym.bean.User;

import com.wym.bussiess.UserDao;

public class LoginAction extends ActionSupport implements ServletContextAware, ServletRequestAware{

private User user;

private HttpServletRequest request;

private HttpSession session;

private ServletContext application;

public LoginAction(){

System.out.println("执行LoginAction构造方法！");

}

public String execute(){

UserDao userDao = new UserDao();

if(userDao.loginUser(user)){

request.setAttribute("a", "this is a");

session.setAttribute("b", "this is b");

application.setAttribute("c", "this is c");

return "success";

}

else{

return "faint";

}

}

public User getUser() {

return user;

}

public void setUser(User user) {

this.user = user;

}

public void setServletContext(ServletContext application) {

// TODO Auto-generated method stub

this.application = application;

}

public void setServletRequest(HttpServletRequest request) {

// TODO Auto-generated method stub

this.request = request;

this.session = request.getSession();

}

}