第01步：配置web.xml，启动struts框架
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter> <filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping> <welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
第02步：编写action类
package com.self.action;
public class InterceptorAction {
private String message ;
public String login(){
this.message="登录成功！";
return "success";
}
public String addUser(){
this.message="添加用户";
return "success";
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
}
第03步：编写拦截器类
package com.self.action; import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;//导入包，包里含有Interceptor类 /**第01 步：编写拦截器**/
public class Permission implements Interceptor { public void destroy() { } public void init() { } public String intercept(ActionInvocation invocation) throws Exception {//属于aop编程的环绕通知
String reString="";
//01：判断用户是否登录，登录就有权限执行action方法，没登陆就没权限
Object user=ActionContext.getContext().getSession().get("user");
if(user!=null){
reString=invocation.invoke();//执行被拦截的action方法，被拦截的action方法有返回的字符串，原样返回
ActionContext.getContext().put("message", "允许执行该操作");
System.out.println("执行拦截的方法，并返回字符串："+reString);
//return invocation.invoke();可以直接这样
}else{
reString="error";
ActionContext.getContext().put("message", "不允许执行该操作！");
System.out.println("执行拦截的方法，并返回字符串："+reString);
}
return reString;//原样返回action方法的字符串
} }
第04步：配置struts.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd"> <struts>
<constant name="struts.action.extension" value="do,action"/>
<!-- 第02步：配置action -->
<package name="intercept" namespace="/" extends="struts-default"> <!-- 第03步：注册拦截器 -->
<interceptors>
<!-- 03.1：自定义拦截器配置 -->
<interceptor name="permission" class="com.self.action.Permission" />
<!-- 03.2 ：定义拦截器栈，不定义会失去很多struts自身的拦截器-->
<interceptor-stack name="permissionStackss">
<!-- 03.4：引入系统拦截器栈：defaultStack，系统拦截器栈放前面，先执行 -->
<interceptor-ref name="defaultStack"/>
<!-- 03.5：引入自定义拦截器 -->
<interceptor-ref name="permission" />
</interceptor-stack>
</interceptors> <global-results>
<result name="error">
/error.jsp
</result>
</global-results>
<action name="list_*" class="com.self.action.InterceptorAction" method="{1}">
<!-- 03.6：自定义拦截器先执行:"permissionStackss"还是"permissionStacks" -->
<interceptor-ref name="permissionStackss" />
<result name="success">
/show.jsp
</result>
</action>
</package>
</struts>
第05步：编写界面，session有数据，拦截器通过
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<html>
<head>
</head>
<body>
<%
request.getSession().setAttribute("user", "zouli");
%>
<center>
<a href="list_login.action">用户登录action！</a><BR>
<a href="list_addUser.action">添加用户action！</a><BR>
</center>
<br>
</body>
</html>
第06步：编写界面，session没数据，拦截器不通过
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<html>
<head>
</head>
<body>
<%
request.getSession().removeAttribute("user");
%>
<center>
没有用户<BR>
<a href="list_login.action">用户登录action！</a><BR>
<a href="list_addUser.action">添加用户action！</a><BR>
</center>
<br>
</body>
</html>
第07步：编写通过显示界面
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<html>
<head>
</head>
<body>
<center>
登录信息：message：${message }
</center>
<br>
</body>
</html>
第08步：编写不通过错误界面
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<html>
<head>
</head>
<body>
<center>
拦截信息：message：${message }<BR>
拦截器不能使用错误！
</center>
</body>
</html>
注意：需要导入包