struts2

struts2 自定义拦截器

2018-05-22  本文已影响0人  DouDouZH

一、为什么要自定义拦截器

在struts2里面有很多拦截器，这些拦截器是struts2封装的功能，但是在实际开发中，struts2里面拦截器中可能没有要使用的功能，这个时候需要自己写拦截器实现功能

二、拦截器的结构

1、源代码看拦截器结构
2、开发中写类，继承
3、让拦截器和action有关系

三、自定义登录拦截器

1、需求

在项目中，有许多action的超链接，实现只有是登录的状态，才可以点击action的超链接实现功能，如果不是登录，点击action链接返回登录页面

2、登录状态：session域对象实现
3、实现登录的基本功能

login.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'login.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>
  
  <body>
    <div align="center">
        <h1>Login</h1>
        <h3 style="color: red">${requestScope.msg }</h3>
        <form action="${pageContext.request.contextPath }/checklogin" method="post">
            username:<input type="text" name="username"/><br><br>
            passwork:<input type="password" name="password"/><br><br>
            <input type="submit" value="login"/>
        </form>
    </div>
  </body>
</html>

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'index.jsp' starting page</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
  </head>
  
  <body>
    <c:if test="${''!=sessionScope.username && null!=sessionScope.username }">
        欢迎 ${sessionScope.username }
    </c:if>
    <c:if test="${''==sessionScope.username || null==sessionScope.username }">
        <a href="${pageContext.request.contextPath }/login.jsp"> 您好请登录！</a>
    </c:if> 
    <br>
      <a href="${pageContext.request.contextPath }/hehe">点我·····</a>
    <br>
    <a href="${pageContext.request.contextPath }/haha">点我·····</a>
  </body>
</html>

CheckLogin.java

package work.zhangdoudou.Action;

import javax.servlet.http.HttpServletRequest;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;

import work.zhangdoudou.Bean.UserBean;

public class CheckLogin extends ActionSupport implements ModelDriven<UserBean>{
    private UserBean user;

    @Override
    public String execute() throws Exception {
        
        HttpServletRequest request=ServletActionContext.getRequest();
        if ("manman".equals(user.getUsername())&&"520".equals(user.getPassword())) {
            // 登录成功
            //向session放值
            request.getSession().setAttribute("username", user.getUsername());
            System.out.println(SUCCESS);
            return SUCCESS;
        }else{
            //登录失败
            request.setAttribute("msg", "账号或密码错误！");
            System.out.println(ERROR);
            return ERROR;
        }
    }
    
    @Override
    public UserBean getModel() {
        if (null==user) {
            user=new UserBean();
        }
        return user;
    }
}

struts.xml

<?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>
    <constant name="false" value="struts.enable.DynamicMethodInvocation"/>
    <constant value="true" name="struts.devMode"/>
    <package name="default" extends="struts-default" namespace="/">
        <!--name：访问名称 -->
        
        <action name="checklogin" method="execute" class="work.zhangdoudou.Action.CheckLogin">
            <result name="success">/index.jsp</result>
            <result name="error">/login.jsp</result>
        </action>
        
    </package>
</struts>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>struts2.Filter</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  
  <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>
  
</web-app>
4、添加登陆拦截器

（1）判断是否登录：判断session里面是否有username的值
（2）拦截器的实现过程

拦截器类Filter.java

package work.zhangdoudou.Filter;

import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.client.Invocation;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.MethodFilterInterceptor;

public class Filter extends MethodFilterInterceptor{
    //这个方法里面写拦截器逻辑
    @Override
    protected String doIntercept(ActionInvocation invocation) throws Exception {

        //判断session是否有username值
        //得到session
        HttpServletRequest request=ServletActionContext.getRequest();
        Object object=request.getSession().getAttribute("username");
        //判断
        if (null!=object) {
            //登陆状态
            //做类似于放行操作
            return invocation.invoke();
        }else{
            //不是登陆状态
            //不登录不执行action的方法，返回登陆页面
            request.setAttribute("msg", "请登录！");
            return "error";
        }   
    }
}

（3）配置action和拦截器的关系（注册拦截器）

<?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>
    <constant name="false" value="struts.enable.DynamicMethodInvocation"/>
    <constant value="true" name="struts.devMode"/>
    <package name="default" extends="struts-default" namespace="/">
        
        <!-- 声明拦截器 -->
        <interceptors>
            <interceptor name="login" class="work.zhangdoudou.Filter.Filter"></interceptor> 
        </interceptors>
    
    
        <!--name：访问名称 -->
        <action name="checklogin" method="execute" class="work.zhangdoudou.Action.CheckLogin">
            <result name="success">/index.jsp</result>
            <result name="error">/login.jsp</result>
        </action>
        
        
        <action name="hehe" method="execute" class="work.zhangdoudou.Action.hehe">
            <!-- 使用自定义的拦截器 -->
            <interceptor-ref name="login"></interceptor-ref>
            <!-- 默认拦截器手动使用一次 -->
            <interceptor-ref name="defaultStack"></interceptor-ref>
            
            <result name="success">/index.jsp</result>
            <result name="error">/login.jsp</result>
        </action>
        
    </package>
</struts>
5、配置拦截器，不要对action的所有方法都进行拦截
<?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>
    <constant name="false" value="struts.enable.DynamicMethodInvocation"/>
    <constant value="true" name="struts.devMode"/>
    <package name="default" extends="struts-default" namespace="/">
        
        <!-- 声明拦截器 -->
        <interceptors>
            <interceptor name="login" class="work.zhangdoudou.Filter.Filter"></interceptor> 
        </interceptors>
    
    
        <!--name：访问名称 -->
        <action name="checklogin" method="execute" class="work.zhangdoudou.Action.CheckLogin">
            <result name="success">/index.jsp</result>
            <result name="error">/login.jsp</result>
        </action>
        
        
        <action name="hehe" method="execute" class="work.zhangdoudou.Action.hehe">
            <!-- 使用自定义的拦截器 -->
            <interceptor-ref name="login"></interceptor-ref>
            <!-- 默认拦截器手动使用一次 -->
            <interceptor-ref name="defaultStack"></interceptor-ref>
            
            <result name="success">/index.jsp</result>
            <result name="error">/login.jsp</result>
        </action>
        
        <action name="haha" method="haha" class="work.zhangdoudou.Action.hehe">
            <!-- 使用自定义的拦截器 -->
            <interceptor-ref name="login">
                <!-- 配置某些方法不进行拦截 name属性excludeMethods -->
                <param name="excludeMethods">haha</param>
            </interceptor-ref>
            <!-- 默认拦截器手动使用一次 -->
            <interceptor-ref name="defaultStack"></interceptor-ref>
            
            <result name="success">/index.jsp</result>
            <result name="error">/login.jsp</result>
        </action>
        
    </package>
</struts>
6、实现效果

点击拦截进行登录


image.png
image.png

点击不拦截


image.png
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