Struts2中操作request,session,application的方法

 

Map类型——request,session,application

真实类型——HttpServletRequest,HttpSession,ServletContext

Map类型是Struts对真实类型的一个封装，会将真实类型映射到Map类型中

取得上述元素有以下4种方法

1  通过ActionContext来访问request,session,application对象

2  通过实现RequestAware、SessionAware、ApplicationAware接口来访问request,session,application对象(常用)

3  通过ServletActionContext来访问request,session,application对象

4  通过实现ServletRequestAware接口来访问request,session,application对象

马士兵老师对这里的内容讲得非常详细，结合马士兵老师的源码来看一下：

第一种方法

package com.bjsxt.struts2.user.action;

import java.util.Map;

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

public class LoginAction1 extends ActionSupport {
 
 private Map request;
 private Map session;
 private Map application;
 
 public LoginAction1() {
  request = (Map)ActionContext.getContext().get("request");
  session = ActionContext.getContext().getSession();
  application = ActionContext.getContext().getApplication();
 }
 
 public String execute() {
  request.put("r1", "r1");
  session.put("s1", "s1");
  application.put("a1", "a1");
  return SUCCESS;
 }

}
通过取得Struts的Action的上下文来取得上述三种元素，map类型的。

方法二

package com.bjsxt.struts2.user.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;

public class LoginAction2 extends ActionSupport implements
RequestAware,SessionAware,
ApplicationAware {
 
 private Map<String, Object> request;
 private Map<String, Object> session;
 private Map<String, Object> application;
 
 // IOC 

 public String execute() {
  request.put("r1", "r1");
  session.put("s1", "s1");
  application.put("a1", "a1");
  return SUCCESS;
 }

 @Override
 public void setRequest(Map<String, Object> request) {
  this.request = request;
 }

 @Override
 public void setSession(Map<String, Object> session) {
  this.session = session;
 }

 @Override
 public void setApplication(Map<String, Object> application) {
  this.application = application;
 }
 
}

通过Struts注入进来三个元素，map类型。

前台jsp页面获取后台值的方式

<s:property value="#request.r1> | <%=request.getAttribute("r1")%>

<s:property value="#session.s1"/> | <%=session.getAttribute("s1")%>

<s:property value="#application.a1"/> | <%=application.getAttribute("a1")%>

方法三

package com.bjsxt.struts2.user.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;

public class LoginAction3 extends ActionSupport {
 
 private HttpServletRequest request;
 private HttpSession session;
 private ServletContext application;
 
 public LoginAction3() {
  request = ServletActionContext.getRequest();
  session = request.getSession();
  application = session.getServletContext();
 }
 
 public String execute() {
  request.setAttribute("r1", "r1");
  session.setAttribute("s1", "s1");
  application.setAttribute("a1", "a1");
  return SUCCESS;
 }
 
}

取得的是真实的类型

方法四

package com.bjsxt.struts2.user.action;

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 LoginAction4 extends ActionSupport implements
ServletRequestAware {
 
 private HttpServletRequest request;
 private HttpSession session;
 private ServletContext application;
 
 
 public String execute() {
  request.setAttribute("r1", "r1");
  session.setAttribute("s1", "s1");
  application.setAttribute("a1", "a1");
  return SUCCESS;
 }

 @Override
 public void setServletRequest(HttpServletRequest request) {
  this.request = request;
  this.session = request.getSession();
  this.application = session.getServletContext();
 }
 
}

依赖注入，取得的是真实类型