struts-核心内容-9-拦截器

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1.拦截器执行流程-重点

启动：

创建所有拦截器，执行init()方法

访问：

先创建Action

再执行拦截器

最后：拦截器放行，执行 execute()方法

拦截器案例

拦截器实现登录验证拦截

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE struts PUBLIC        "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"        "http://struts.apache.org/dtds/struts-2.3.dtd"><struts>    <package name="user" extends="struts-default">        <!--拦截器配置-->        <interceptors>            <interceptor name="loginCheck" class="com.cx.interceptor.UserCheckInterceptor"></interceptor>            <interceptor-stack name="myStack">                <interceptor-ref name="defaultStack"></interceptor-ref>                <interceptor-ref name="loginCheck"></interceptor-ref>            </interceptor-stack>        </interceptors>        <!--执行拦截器-->        <default-interceptor-ref name="myStack"></default-interceptor-ref>        <global-results>            <result name="error">/error.jsp</result>        </global-results>        <action name="user_*" class="com.cx.action.UserAction" method="{1}">            <!--user_list也可访问-->            <!--登录失败-->            <result name="input">/login.jsp</result>            <!--成功-->            <result name="loginSuccess" type="redirectAction">user_list</result>            <!--列表展示-->            <result name="list">/WEB-INF/list.jsp</result>        </action>    </package></struts>

UserAction.java

package com.cx.action;import com.cx.entity.Admin;import com.cx.service.AdminService;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;import java.util.List;/** * Created by cxspace on 16-7-13. */public class UserAction extends ActionSupport{    //自动注入    private Admin admin;    public Admin getAdmin() {        return admin;    }    public void setAdmin(Admin admin) {        this.admin = admin;    }    private AdminService adminService = new AdminService();    /*        封装请求数据     */    /*       调用service     */    //登录    public String login() throws Exception {        Admin userInfo = adminService.login(admin);        //判断登录逻辑        try {            if (userInfo == null) {                return "input";            }            ActionContext.getContext().getSession().put("userInfo", userInfo);            return "loginSuccess";        }        catch (Exception e)        {            return ERROR;        }    }    //列表    public String list() throws Exception {        try {            List<Admin> list = adminService.getAll();            ActionContext.getContext().getContextMap().put("listAdmin", list);            return "list";        }catch (Exception e){            return ERROR;        }    }}

//拦截器
package com.cx.interceptor;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionInvocation;import com.opensymphony.xwork2.ActionProxy;import com.opensymphony.xwork2.interceptor.AbstractInterceptor;/** * Created by cxspace on 16-7-13. */public class UserCheckInterceptor extends AbstractInterceptor {    @Override    public String intercept(ActionInvocation actionInvocation) throws Exception {        //获取actionContext对象        ActionContext ac = actionInvocation.getInvocationContext();        //拿到当前执行的方法名，判断，只有login才可进入        // 获取action类的代理对象        ActionProxy proxy = actionInvocation.getProxy();        //获取当前执行的方法名        String methodName = proxy.getMethod();        if (!"login".equals(methodName))        {            //判断是否已登录            Object obj = ac.getSession().get("userInfo");            if(obj==null){                return "input";            }            else {                return actionInvocation.invoke();            }        }else {            return actionInvocation.invoke();        }    }}

完整实例github地址

https://github.com/cxspace/Interceptor

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