struts2取得request,session,appilcation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


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