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struts2拦截器

struts2拦截器

作者: liangxifeng833 | 来源:发表于2018-01-22 20:24 被阅读9次

一.struts2框架整体流程

struts2-3.jpg Paste_Image.png Paste_Image.png

二.第一个demo

1.创建被拦截的action

package com.lxf.timerintercepter;
/**
 * 做一个耗时的actioin,用拦截器统计该action执行的时间
 */

import com.opensymphony.xwork2.ActionSupport;

public class TimerAction extends ActionSupport{

    @Override
    public String execute() throws Exception {
            for(int i=0;i<10000;i++)
            {
                System.out.println("I LOVE IMOOC");
            }
            return SUCCESS;
    }
    
}

2.创建拦截器

package com.lxf.timerintercepter;
/**
 * 拦截器,用来计算timerAction的执行时间
 */

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

public class TimerIntercepter extends AbstractInterceptor {

    /**
     * 自动调用此方法,进行拦截操作
     */
    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
           //1.执行Action之前
           long start = System.currentTimeMillis(); //获得当前的毫秒值
           //2.执行下一个拦截器,如果已经是最后一个拦截器,则执行目标action
           String res = invocation.invoke();
           //3.执行Action之后
           long end = System.currentTimeMillis(); 
           System.out.println("执行Action话费的时间:" + (end - start) + "ms");
           //将最终调用Action之后的结果视图返回   
           return res;
    }

}

3.在Timer.xml中注册和在对应action中引用拦截器

<?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>
    <package name="default2" namespace="/myTimer" extends="struts-default">
        <!-- 注册拦截器 -->
        <interceptors>
            <interceptor name="mytimer"  class="com.lxf.timerintercepter.TimerIntercepter"></interceptor>
        </interceptors>
        <action name="timerAction" class="com.lxf.timerintercepter.TimerAction">
            <result>/result.jsp</result>
            <!-- 引用拦截器 -->
            <interceptor-ref name="mytimer"></interceptor-ref>
        </action>
    </package>
</struts>   

4.在struts.xml中包含timer.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>
    <!-- 使用include标签引入各个模块xml配置文件 -->
    <include file="helloworld.xml"></include>
    <include file="helloworld2.xml"></include>
    <!-- 引入测试action执行时间xml的配置文件 -->
     <include file="timer.xml"></include>
    
    
    <constant name="struts.i18n.encoding" value="UTF-8"></constant>
    
    <!-- 使用感叹号方式配置多个method -->
    <constant name="struts.enable.DynamicMethodInvocation" value="true"></constant>
    <!-- 配置action后缀 -->
    <constant name="struts.action.extension" value="html,action,do"></constant>
</struts>   

5.将项目部署到tomcat上,访问地址:

http://localhost:8081/struts2-test1/myTimer/timerAction.action

查看控制台拦截器产生作用:

...
I LOVE IMOOC
I LOVE IMOOC
I LOVE IMOOC
执行Action话费的时间:29ms

三.struts2内置拦截器

Paste_Image.png Paste_Image.png
  • 内置拦截器我们可以查看struts2核心jar包struts2-core-2.3.1.jar中的struts-default.xml

  • 在struts-default.xml中配置了默认拦截器栈


    Paste_Image.png
  • 所以推荐在自己显示为某个action引用拦截器之前,将默认拦截器栈先手动引用

<?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>
    <package name="default2" namespace="/myTimer" extends="struts-default">
        <!-- 注册拦截器 -->
        <interceptors>
            <interceptor name="mytimer"  class="com.lxf.timerintercepter.TimerIntercepter"></interceptor>
        </interceptors>
        <action name="timerAction" class="com.lxf.timerintercepter.TimerAction">
            <result>/result.jsp</result>
            <!-- 为Action显示引用拦截器后,默认的拦截器defaultStack不在生效,需要手工引用 -->
            <interceptor-ref name="defaultStack"></interceptor-ref>
            <!-- 引用拦截器 -->
            <interceptor-ref name="mytimer"></interceptor-ref>
        </action>
    </package>
</struts>   

四.使用拦截器实现对用户登录验证

1.在WEB_INF目录中简历/page/manager.jsp,作为用户后台页面.

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
后台管理页面,只有已登录的页面才能够访问!
</body>
</html>

2.写loginNew.jsp登录页

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h2>用户登陆</h2>
${loginError}
<form  action="loginNew.action" method="post">
    用户名:<input type="text" name="username"  />
    密码:<input type="password" name="password" />
    <input type="submit" value="登录" />
</form>
</body>
</html> 

3.写登录LoginNewAction.java

package com.lxf.action;
/**
 * 用户登录页面,用来判断用户是否登录
 */

import java.util.Map;

import org.apache.struts2.interceptor.SessionAware;

import com.opensymphony.xwork2.ActionSupport;

public class LoginNewAction extends ActionSupport implements SessionAware{
    private String username;
    private String password;
    private Map<String,Object> session;
    /**
     * 实现SessionAware中的接口
     */
    @Override
    public void setSession(Map<String, Object> session) {
        this.session = session;
        // TODO Auto-generated method stub
    }
    
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;   
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    
    /**
     * 处理登录请求
     */
    public String loginNew()    
    {
        if("admin".equals(username) && "123".equals(password))
        {
            session.put("loginInfo", username);
            return SUCCESS;
        }else
        {
            session.put("loginError", "用户名或密码不正确!");
            return ERROR;
        }
    }
}

4.写AuthIntercepter.java拦截器

package com.lxf.timerintercepter;
/**
 * 拦截器,用来验证用户登录
 */

import java.util.Map;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;

public class AuthIntercepter extends AbstractInterceptor {

    /**
     * 自动调用此方法,进行拦截操作
     */
    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
           ActionContext context = ActionContext.getContext();
           Map<String,Object> session = context.getSession();
           //用户已登录
           if(session.get("loginInfo") !=null)
           {
               String result = invocation.invoke();
               return result;
           }else
            //用户未登录
           {
               return "login";
           }
    }
}

4.配置自定义manager.xml配置文件:

<?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">
 <!-- 后台管理配置文件,判断用户登录 -->
<struts>
    <package name="default5" namespace="/manager" extends="struts-default">
        <!-- 注册拦截器 -->
        <interceptors>
            <interceptor name="auth" class="com.lxf.timerintercepter.AuthIntercepter"></interceptor>
            <!-- 自定义拦截器栈myStack,组合了defaultStack和auth -->
            <interceptor-stack name="myStack">
                <interceptor-ref name="defaultStack"></interceptor-ref>
                <interceptor-ref name="auth"></interceptor-ref>
            </interceptor-stack>
        </interceptors>
        
        <!-- 通过Action访问后台管理页面,需要判断用户是否已登录,如果未登录则跳转到登录页 -->
        <action name="auth">
            <result>/WEB-INF/page/manager.jsp</result>
            <result name="login">/loginNew.jsp</result>
            <!-- 引用自定义拦截器栈 -->
            <interceptor-ref name="myStack"></interceptor-ref>
        </action>
        
        <!-- 登录action -->
        <action name="loginNew" class="com.lxf.action.LoginNewAction" method="loginNew">
            <result>/WEB-INF/page/manager.jsp</result>
            <result name="error">/loginNew.jsp</result>
        </action>
    </package>
</struts>   

5.在struts.xml中引用manager.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>
    <!-- 使用include标签引入各个模块xml配置文件 -->
    <include file="helloworld.xml"></include>
    <include file="helloworld2.xml"></include>
    <!-- 引入测试action执行时间xml的配置文件 -->
     <include file="timer.xml"></include>
    <!-- 引入后台管理配置文件,判断用户登录xml -->
     <include file="manager.xml"></include>
    
    
    <constant name="struts.i18n.encoding" value="UTF-8"></constant>
    
    <!-- 使用感叹号方式配置多个method -->
    <constant name="struts.enable.DynamicMethodInvocation" value="true"></constant>
    <!-- 配置action后缀 -->
    <constant name="struts.action.extension" value="html,action,do"></constant>
    <!-- 打开开发模式 -->
    <constant name="struts.devMode" value="true"></constant>
</struts>   

6.在没有登录的情况下,访问:

http://localhost:8081/struts2-test1/manager/auth.action

过滤器会判断是否登录,如果登录了则跳转套manager.jsp页面,否则跳转套登录页面

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