struts2 已有拦截器使用以及自定义拦截器使用

1.struts2 已有拦截器的使用

官方文档解释：拦截器是动态拦截Action调用的对象，拦截器提供一种机制，允许开发者定义一段Action执行前或执行后的代码，也允许在一个Action执行前阻止其执行。

在struts2-core-..jar包里，有struts-default.xml，这里定义了已有的拦截器。想使用的话，直接在自己工程的struts.xml中加入代码：

<include file="struts-default.xml"></include>

例如，使用已有的timer拦截器，struts配置如下：

 1 <!DOCTYPE struts PUBLIC
 2 "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
 3 "http://struts.apache.org/dtds/struts-2.0.dtd">
 4 <struts>
 5 <include file ="struts-default.xml"/>
 6 <package name ="wen" extends ="struts-default">
 7  <action name ="Timer" class ="wen.TimerInterceptorAction">
 8   <interceptor-ref name ="timer"/>
 9    <result>/Timer.jsp</result>
10 </action>
11 </package>
12 </struts>

 

2.struts2 自定义拦截器的使用

我的工程目录如下：

 

 

 

为了方便理解，在代码里添加了后台打印

 

 

 

 

 

 

（1）AuthorizatedAccess.java  模拟访问受限资源

 1 package com.action;
 2 
 3 import com.opensymphony.xwork2.ActionSupport;
 4 
 5 public class AuthorizatedAccess extends ActionSupport implements RoleAware{
 6 
 7     private String role;
 8     public void setRole(String role) {
 9         // TODO Auto-generated method stub
10         System.out.println(AuthorizationInterceptor.counter++ + " AuthorizatedAccess setRole " + role);
11         this.role = role;
12     }
13     public String getRole(){
14         System.out.println(AuthorizationInterceptor.counter++ + " AuthorizatedAccess getRole " + role);
15         return role;
16     }
17     @Override
18     public String execute() throws Exception {
19         // TODO Auto-generated method stub
20         System.out.println(AuthorizationInterceptor.counter++ + " AuthorizatedAccess.execute()");
21         return SUCCESS;
22     }
23 }

（2）AuthorizationInterceptor.java  自定义拦截器

 1 package com.action;
 2 
 3 import java.util.Map;
 4 
 5 import org.omg.CORBA.PUBLIC_MEMBER;
 6 
 7 import com.opensymphony.xwork2.Action;
 8 import com.opensymphony.xwork2.ActionInvocation;
 9 import com.opensymphony.xwork2.interceptor.AbstractInterceptor;
10 import com.sun.org.apache.commons.collections.StaticBucketMap;
11 
12 public class AuthorizationInterceptor extends AbstractInterceptor{
13     public static int counter = 0;
14     
15     @Override
16     public String intercept(ActionInvocation ai) throws Exception {
17         // TODO Auto-generated method stub
18         Map session = ai.getInvocationContext().getSession();
19         String role = (String)session.get("ROLE");
20         if (null != role) {
21             System.out.println(counter++ + " AuthorizationInterceptor  role != null .......and role===" + role);
22             Object object = ai.getAction();
23             if (object instanceof RoleAware) {
24                 RoleAware action = (RoleAware)object;
25                 action.setRole(role);
26             }
27             String hahaString = ai.invoke();
28             System.out.println(counter++ + " AuthorizationInterceptor ai.invoke()====" + hahaString);
29             return haha;
30         }else {
31             System.out.println(counter++ + " AuthorizationInterceptor role == null .......");
32             return Action.LOGIN;
33         }
34     }
35 
36 }

（3）Login.java

 1 package com.action;
 2 
 3 import java.util.Map;
 4 
 5 import org.apache.struts2.interceptor.SessionAware;
 6 
 7 import com.opensymphony.xwork2.ActionSupport;
 8 
 9 public class Login extends ActionSupport implements SessionAware{
10     private String role;
11     private Map session;
12     public String getRole(){
13         System.out.println(AuthorizationInterceptor.counter++ + " Login getRole()...." + role);
14         return role;
15     }
16     
17     public void setRole(String role){
18         System.out.println(AuthorizationInterceptor.counter++ + " Login setRole()...." + role);
19         this.role = role;
20     }
21     public void setSession(Map session) {
22         // TODO Auto-generated method stub
23         this.session = session;
24         System.out.println(AuthorizationInterceptor.counter++ + " Login setSession=====" + session);
25     }
26 
27     @Override
28     public String execute() throws Exception {
29         // TODO Auto-generated method stub
30         System.out.println(AuthorizationInterceptor.counter++ + " Login execute 获取role======" + role);
31         session.put("ROLE", role);
32         return SUCCESS;
33     }    
34 }

（4）RoleAware.java

1 package com.action;
2 
3 public interface RoleAware {
4     void setRole(String role);
5 }

（5）Roles.java

 1 package com.lihui;
 2 
 3 import java.util.HashMap;
 4 import java.util.Map;
 5 
 6 public class Roles {
 7     public Map<String, String> getRoles(){
 8         Map<String, String> roles = new HashMap<String, String>();
 9         roles.put("EMPLOYEE", "员工");
10         roles.put("MANAGER", "老板");
11         return roles;
12     }
13 }

（6）Login.jsp

 1 <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
 2 <%@ taglib prefix="s" uri="/struts-tags"%>
 3 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 4 <html>
 5   <head>  
 6     <title>登录</title>
 7   </head>
 8   
 9   <body>
10     <h1>Login</h1>
11     请选择一个角色：
12     <s:bean id="roles" name="com.lihui.Roles"/>
13     <s:form action="login">
14         <s:radio list="#roles.roles" value="EMPLOYEE" name="role" label="角色"></s:radio>
15         <s:submit value="提交"></s:submit>
16     </s:form>
17   </body>
18 </html>

（7）ShowUser.jsp

 1 <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
 2 <%@ taglib prefix="s" uri="/struts-tags" %>
 3 
 4 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 5 <html>
 6   <head>   
 7     <title>显示用户的角色</title>
 8   </head>
 9   
10   <body>
11     <h1>您的角色是：
12     <s:property value="role"/>
13     </h1>
14   </body>
15 </html>

（8）struts.xml

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE struts PUBLIC
 3     "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
 4     "http://struts.apache.org/dtds/struts-2.0.dtd">
 5 <struts>
 6     <include file="struts-default.xml"></include>
 7     <package name="com.action" extends="struts-default" namespace="/test">
 8         <interceptors>
 9             <interceptor name="auth" class="com.action.AuthorizationInterceptor"></interceptor>
10         </interceptors>
11         <action name="login" class="com.action.Login">
12             <result type="chain">
13                 <param name="actionName">authorizatedAccess</param>
14                 <param name="namespace">/test</param>
15             </result>
16         </action>
17         <action name="authorizatedAccess" class="com.action.AuthorizatedAccess">
18             <interceptor-ref name="auth"></interceptor-ref>
19             <result name="success">/pages/ShowUser.jsp</result>
20             <result name="SUCCESS">/pages/ShowUser.jsp</result>
21             <result name="login">/pages/Login.jsp</result>           
22         </action>
23     </package>
24 </struts>

然后输入网址：http://localhost:8080/Struts2Proj/test/authorizatedAccess.action 之所以中间还有个 /test 是因为程序中用了命名空间 namespace="/test"。而又之所以使用命名空间是因为在配置 struts.xml 时报错。

网页显示如下：

 

第二个图是在一个图选择了员工并点击提交之后显示的界面。至于程序到底是怎么运行的，看一下后台输出就知道了。

0：一开始的时候 Role 肯定是空的，所以直接跳向登录界面。

在登录界面，选择了某个角色之后，点击提交，根据struts.xlml 首先会调用登录类 Login.java ，然后跳转到AuthorizatedAccess这个action，然后在这个action调用时先调用拦截器，如果role不为空，则通过 ai.invoke() 来调用AuthorizationInterceptor.java ，最后根据 AuthorizationInterceptor.java   的返回结果确定调用 Login.jsp 还是 ShowUser.jsp.