Struts2_访问Web元素

取得Map 类型的 request,session,application, HttpServletRequest,HttpSession,ServletContext的引用。

分访问 Map 类型和原始类型两种。

1、获取 Map 类型的request,session,application（ Map 类型）的第一种方式，他们保存在都ActionContext中：

 package com.bjsxt.struts2.user.action;

 import java.util.Map;

 import com.bjsxt.struts2.user.model.User;
 import com.opensymphony.xwork2.ActionContext;
 import com.opensymphony.xwork2.ActionSupport;

 public class LoginAction1 extends ActionSupport{

     private static final long serialVersionUID = -7767523825141043349L;

     private Map request;
     private Map session;
     private Map application;

     private User user;

     public LoginAction1(){
         //在 对应方法中或者在构造方法中获取都一样
         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;
     }

     public User getUser() {
         return user;
     }

     public void setUser(User user) {
         this.user = user;
     }

 }

jsp页面的访问：

 <s:property value="#request.r1"/>
 <s:property value="#session.s1"/>
 <s:property value="#application.a1"/>

2、获取 Map 类型的request,session,application的第一种方式，一般用这种就行了：

实现了RequestAware,SessionAware,ApplicationAware 这三个接口，这种方式是通过Struts2把这三个对象注入给Action的。

 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.bjsxt.struts2.user.model.User;
 import com.opensymphony.xwork2.ActionSupport;

 /**
  * 只用这种
  * @author Administrator
  *
  */
 public class LoginAction2 extends ActionSupport implements RequestAware,SessionAware,ApplicationAware{

     private static final long serialVersionUID = -7767523825141043349L;

     private Map<String, Object> request;
     private Map<String, Object> session;
     private Map<String, Object> application;

     private User user;

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

     public User getUser() {
         return user;
     }

     public void setUser(User user) {
         this.user = user;
     }

     public Map<String, Object> getRequest() {
         return request;
     }

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

     public Map<String, Object> getSession() {
         return session;
     }

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

     public Map<String, Object> getApplication() {
         return application;
     }

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

 }

获取的方式跟第一种是一样的。

3、获取 HttpServletRequest,HttpSession,ServletContext （原始类型）的第一种方式：

 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 static final long serialVersionUID = -7767523825141043349L;

     private HttpServletRequest request;
     private HttpSession session;
     private ServletContext application;

     public LoginAction3(){
         request = ServletActionContext.getRequest();
         session = request.getSession();
         application = session.getServletContext();
     }

     public String execute(){

         return SUCCESS;
     }
 }

取值，要是request、session、application中存在这个属性的话：

 <%=request.getAttribute("r1") %>
 <%=session.getAttribute("s1") %>
 <%=application.getAttribute("a1") %>

4、获取 HttpServletRequest,HttpSession,ServletContext （原始类型）的第二种方式：

 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 org.apache.struts2.interceptor.ServletRequestAware;

 import com.opensymphony.xwork2.ActionSupport;

 public class LoginAction4 extends ActionSupport implements ServletRequestAware{

     private static final long serialVersionUID = -7767523825141043349L;

     private HttpServletRequest request;
     private HttpSession session;
     private ServletContext application;

     public String execute(){
         return SUCCESS;
     }

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

 }

取值方式和第三种一样。

补充：

<s:property value="#attr.r1"/> <s:property value="#attr.s1"/> <s:property value="#attr.a1"/>

这种获取方式会去ActionContext中遍历查找，所有的r1、s1、a1的值，一般情况下我们都会知道变量的值精确存放点，不推荐使用这个取值方式。

链接: http://pan.baidu.com/s/1pLk9ZCJ 密码: idbm