struts自定义拦截器

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