struts2 Action中获取request, response,Session对象的方法
非IoC方式
要获得上述对象，关键Struts 2.0中com.opensymphony.xwork2.ActionContext类。我们可以通过它的静态方法getContext()获取当前 Action的上下文对象。 另外，org.apache.struts2.ServletActionContext作为辅助类（Helper Class），可以帮助您快捷地获得这几个对象。
写个例子测试一下：
请求的页面是：
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head><title>Simple ha page</title></head>
<body>
<h3>hahaha</h3>
<h3>you success,ha</h3>
<br>
request---<%=request.getAttribute("request") %><br>
request2----<%=request.getAttribute("request2") %><br>
session--<%=session.getAttribute("session") %><br>
<br>------
session2--<%=session.getAttribute("session2") %><br>
session3--<%=session.getAttribute("session3") %><br>
session4--<%=session.getAttribute("session4") %><br>
session5--<%=session.getAttribute("session5") %><br>
session6--<%=session.getAttribute("session6") %><br>
</body>
</html>
要获得上述对象，关键Struts 2.0中com.opensymphony.xwork2.ActionContext类。我们可以通过它的静态方法getContext()获取当前 Action的上下文对象。 另外，org.apache.struts2.ServletActionContext作为辅助类（Helper Class），可以帮助您快捷地获得这几个对象。
<pre name="code" class="java"><pre name="code" class="java">///我们平时用的，这个很好理解
HttpServletRequest request = ServletActionContext.getRequest ();
HttpServletResponse response=ServletActionContext.getResponse();
HttpSession session=ServletActionContext.getRequest().getSession();
///////通过ActionContext获得
ActionContext ac = ActionContext.getContext();
//request
HttpServletRequest request2 = (HttpServletRequest)ac.get(ServletActionContext.HTTP_REQUEST);
//response
HttpServletResponse response2 = (HttpServletResponse)ac.get(ServletActionContext.HTTP_RESPONSE);
//session以下是错误的，会报异常
java.lang.ClassCastException:
org.apache.struts2.dispatcher.SessionMap cannot be cast to javax.servlet.http.HttpSession
//对于session因为从ActionContext 获取的是Map类型，不能强转化成HttpSession类型，这是ActionContext与ServletActionContext的区别<pre name="code" class="java"><pre name="code" class="java"><pre name="code" class="java">
HttpSession session2=(HttpSession)ac.get(ServletActionContext.SESSION);//错
HttpSession session3=(HttpSession)ac.getContext().getSession();//同上
HttpSession session4=(HttpSession)ac.get(ActionContext.SESSION);//错
//session对象被封装成Map，我们对Map操作就可以
Map session5=ac.getSession();
Map session6=ServletActionContext.getContext().getSession();
session5.put("key5", "value5");
session6.put("key6", "value6");
写个例子测试一下：
package com.visit.frame.test;
import java.util.Map;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.struts2.*;
import org.apache.struts2.dispatcher.*;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class HelloAction extends ActionSupport{
private String leaveMessage;
public String execute(){
this.setLeaveMessage("here me");
///我们平时用的，这个很好理解
HttpServletRequest request = ServletActionContext.getRequest ();
// HttpServletResponse response=ServletActionContext.getResponse();
HttpSession session=ServletActionContext.getRequest().getSession();
///////通过ActionContext获得
ActionContext ac = ActionContext.getContext();
//request
HttpServletRequest request2 = (HttpServletRequest)ac.get(ServletActionContext.HTTP_REQUEST);
//response
// HttpServletResponse response2 = (HttpServletResponse)ac.get(ServletActionContext.HTTP_RESPONSE);
//session
Map session2= (Map) ac.get(ServletActionContext.SESSION);
Map session3=ac.getContext().getSession();//同上
Map session4=(Map) ac.get(ActionContext.SESSION);
//session对象被封装成Map，我们对Map操作就可以
Map session5=(Map)ac.getSession();
Map session6=ServletActionContext.getContext().getSession();
//
request.setAttribute("request", "request0");
session.setAttribute("session", "session0");
request2.setAttribute("request2", "request2");
session2.put("session2", "session2");
session3.put("session3", "session3");
session4.put("session4", "session4");
session5.put("session5", "session5");
session6.put("session6", "session6");
return SUCCESS;
}
public String getLeaveMessage() {
this.leaveMessage="hhhh";
return leaveMessage;
}
public void setLeaveMessage(String leaveMessage) {
this.leaveMessage = leaveMessage;
}
}
请求的页面是：
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head><title>Simple ha page</title></head>
<body>
<h3>hahaha</h3>
<h3>you success,ha</h3>
<br>
request---<%=request.getAttribute("request") %><br>
request2----<%=request.getAttribute("request2") %><br>
session--<%=session.getAttribute("session") %><br>
<br>------
session2--<%=session.getAttribute("session2") %><br>
session3--<%=session.getAttribute("session3") %><br>
session4--<%=session.getAttribute("session4") %><br>
session5--<%=session.getAttribute("session5") %><br>
session6--<%=session.getAttribute("session6") %><br>
</body>
</html>