访问web元素

分别介绍两种方法来取得request、session、application和 HttpServletRequest、HttpSession、ServletContext

这里是第一种方法，不过不常用，过于依赖于容器

Java代码

1. public class LoginAction extends ActionSupport {    
2.         
3.     private Map request;    
4.     private Map session;    
5.     private Map application;    
6.         
7.     public LoginAction1() {    
8.         request = (Map)ActionContext.getContext().get("request");    
9.         session = ActionContext.getContext().getSession();    
10.         application = ActionContext.getContext().getApplication();    
11.     }    
12.     
13.        public String execute() {    
14.         request.put("r1", "r1");    
15.         session.put("s1", "s1");    
16.         application.put("a1", "a1");    
17.         return SUCCESS;     
18.     }    
19.         
20. }    

public class LoginAction 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;       }        }  

第二种方法：这种方法最常用！！！！struts标签访问，加“#”。
//只用这种方法！！！这种方法最常用（而且中间涉及到一种思想：控制反转或称依赖注入）

Java代码

1. package dalei;  
2. import java.util.Map;  
3. import org.apache.struts2.interceptor.ApplicationAware;  
4. import org.apache.struts2.interceptor.RequestAware;  
5. import org.apache.struts2.interceptor.SessionAware;  
6. import com.opensymphony.xwork2.ActionSupport;  
7. public class Action_02 extends ActionSupport implements RequestAware,  
8.         SessionAware, ApplicationAware {  
9.     //IoC inverse of control（控制反转）  
10.     //DI dependency injection（依赖注入）  
11.     private Map<String, Object> request;  
12.     private Map<String, Object> session;  
13.     private Map<String, Object> application;  
14.     //因为是Map类型的数据，所以不能再用以前的setAttribute。  
15.     public String execute() {  
16.         request.put("r1", "r1");  
17.         session.put("s1", "s1");  
18.         application.put("a1", "a1");  
19.         return SUCCESS;  
20.     }  
21.     //负责把三个元素new()出来，容器帮忙来初始化。  
22.     @Override  
23.     public void setRequest(Map<String, Object> request) {  
24.         this.request = request;  
25.     }  
26.     @Override  
27.     public void setSession(Map<String, Object> session) {  
28.         this.session = session;  
29.     }  
30.     @Override  
31.     public void setApplication(Map<String, Object> application) {  
32.         this.application = application;  
33.     }  
34. }                                                                
35.   
36.                                                        Action_02.java  

package dalei;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.ActionSupport;public class Action_02 extends ActionSupport implements RequestAware,SessionAware, ApplicationAware {//IoC inverse of control（控制反转）//DI dependency injection（依赖注入）private Map<String, Object> request;private Map<String, Object> session;private Map<String, Object> application;//因为是Map类型的数据，所以不能再用以前的setAttribute。public String execute() {request.put("r1", "r1");session.put("s1", "s1");application.put("a1", "a1");return SUCCESS;}//负责把三个元素new()出来，容器帮忙来初始化。@Overridepublic void setRequest(Map<String, Object> request) {this.request = request;}@Overridepublic void setSession(Map<String, Object> session) {this.session = session;}@Overridepublic void setApplication(Map<String, Object> application) {this.application = application;}}                                                                                                                     Action_02.java

1. <action name="er"class="dalei.Action_02">  
2.            <result>  
3.               /hello.jsp  
4.            </result>  
5.        </action>                    
6. 
   

 <action name="er"class="dalei.Action_02">            <result>               /hello.jsp            </result>        </action>                                                                      struts.xml

struts中，jsp页面取context中的值：

1. <s:property value="#request.r1"/> | <%=request.getAttribute("r1") %><br>  
2.     <s:property value="#session.s1"/>  |  <%=session.getAttribute("s1") %><br>  
3.     <s:property value="#application.a1"/>  |  <%=application.getAttribute("a1")%><br>  
4.    <s:debug />  
5.                                                   hello.jsp  

……<%@taglib uri="/struts-tags" prefix="s" %>……<body>……<s:property value="#request.r1"/> | <%=request.getAttribute("r1") %><br>    <s:property value="#session.s1"/>  |  <%=session.getAttribute("s1") %><br>    <s:property value="#application.a1"/>  |  <%=application.getAttribute("a1")%><br>   <s:debug />……  </body>……                                                                                                                      hello.jsp

第三种方法

Java代码

1. import javax.servlet.ServletContext;    
2. import javax.servlet.http.HttpServletRequest;    
3. import javax.servlet.http.HttpSession;     
4. import org.apache.struts2.ServletActionContext;    
5. import com.opensymphony.xwork2.ActionSupport;    
6.     
7. public class LoginAction3 extends ActionSupport {    
8.         
9.     private HttpServletRequest request;    
10.     private HttpSession session;    
11.     private ServletContext application;    
12.         
13.     public LoginAction3() {    
14.         request = ServletActionContext.getRequest();    
15.         session = request.getSession();    
16.         application = session.getServletContext();    
17.     }    
18.         
19.     public String execute() {    
20.         request.setAttribute("r1", "r1");    
21.         session.setAttribute("s1", "s1");    
22.         application.setAttribute("a1", "a1");    
23.         return SUCCESS;     
24.     }    
25.         
26. }    

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 LoginAction() {          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;       }        }  

第四种方法

Java代码

1. import javax.servlet.ServletContext;    
2. import javax.servlet.http.HttpServletRequest;    
3. import javax.servlet.http.HttpSession;    
4.     
5. import org.apache.struts2.interceptor.ServletRequestAware;    
6.     
7. import com.opensymphony.xwork2.ActionSupport;    
8.     
9. public class LoginAction extends ActionSupport implements ServletRequestAware {    
10.         
11.     private HttpServletRequest request;    
12.     private HttpSession session;    
13.     private ServletContext application;    
14.         
15.     public String execute() {    
16.         request.setAttribute("r1", "r1");    
17.         session.setAttribute("s1", "s1");    
18.         application.setAttribute("a1", "a1");    
19.         return SUCCESS;     
20.     }    
21.     
22.     @Override    
23.     public void setServletRequest(HttpServletRequest request) {    
24.         this.request = request;    
25.         this.session = request.getSession();    
26.         this.application = session.getServletContext();    
27.     }    
28.         
29. }