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Struts2_访问Web元素

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12/02
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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

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