struts-拦截器应用

一.总体步骤:

1. 自定义一个实现Interceptor接口（或者继承自AbstractInterceptor）的类。

2. 在strutx.xml中注册定义的拦截器。

3. 在需要使用的Action中引用上述定义的拦截器，为了方便也可将拦截器定义为默认的拦截器，这样在不加特殊声明的情况下所有的Action都被这个拦截器拦截。

二.继承自AbstractInterceptor的类

package com.yztc.struts.inteceptor;


import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;

public class DemoInteceptor implements Interceptor {
    public DemoInteceptor() {
    }

    @Override
    public void destroy() {
        System.out.println("Interceptor:被消毁");
    }

    @Override
    public void init() {
        System.out.println("Interceptor:初始化");
    }
    @Override
    public String intercept(ActionInvocation actionInvocation) throws Exception {
        System.out.println("Interceptor:核心方法执行前");
        String invoke = actionInvocation.invoke();
        System.out.println("Interceptor:核心方法执行后");
        return invoke;
    }
}

三.在struts.xml中注册定义的拦截器

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
        "http://struts.apache.org/dtds/struts-2.5.dtd">
<struts>
    <constant name="struts.devMode" value="true"/>
    <constant name="struts.enable.DynamicMethodInvocation" value="true"/>
    <package name="default" extends="struts-default" namespace="/">
        <interceptors>
            <interceptor name="inteceptor1" class="com.yztc.struts.inteceptor.DemoInteceptor">
                <param name="includeMethods" >test</param>
            </interceptor>
            <!--<interceptor name="inteceptor2" class="com.yztc.struts.inteceptor.Demo2Inteceptor">-->
                <!--<param name="includeMethods" >test</param>-->
            <!--</interceptor>-->
            <!--<interceptor name="inteceptor3" class="com.yztc.struts.inteceptor.Demo3Inteceptor">-->
                <!--<param name="includeMethods" >test</param>-->
            <!--</interceptor>-->
        </interceptors>
        <action name="*" class="com.yztc.struts.action.InterceptorAction" method="{1}">
            <result name="success">/Interceptor.jsp</result>
            <interceptor-ref name="inteceptor1"/>
            <!--<interceptor-ref name="inteceptor2"/>-->
            <!--<interceptor-ref name="inteceptor3"/>-->
            <allowed-methods>test</allowed-methods>
        </action>
    </package>
</struts>

四.在需要使用的action中引用上述的拦截器

package com.yztc.struts.action;

import com.opensymphony.xwork2.ActionSupport;

/**
 * _ooOoo_
 * o8888888o
 * 88" . "88
 * (| -_- |)
 * O = /O
 * ___/`---'\____
 * .   ' \| |// `.
 * / \||| : |||// 
 * / _||||| -:- |||||- 
 * | | \ - /// | |
 * | \_| ''---/'' | |
 *  .-\__ `-` ___/-. /
 * ___`. .' /--.-- `. . __
 * ."" '< `.___\_<|>_/___.' >'"".
 * | | : `- \`.;` _ /`;.`/ - ` : | |
 *   `-. \_ __ /__ _/ .-` / /
 * ======`-.____`-.___\_____/___.-`____.-'======
 * `=---='
 * .............................................
 *
 * @author bindu
 * @date 2017-10-25 10:39
 */


public class InterceptorAction extends ActionSupport {
    public String test(){
        System.out.println("核心方法被执行");
        return SUCCESS;
    }
}

五.在web.xml 设置过滤器以及annotation初始化参数

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                      http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
  <display-name>Archetype Created Web Application</display-name>
  <filter>
    <filter-name>StrutsPrepareAndExecuteFilter</filter-name>
    <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>StrutsPrepareAndExecuteFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>