【Spring MVC】教程——使用拦截器实现权限控制

之前一直都在用mvc的拦截器权限控制，后来上网也研究了一些这方面的知识，下面就直接分享下我对mvc的拦截器的理解，通过项目来分析吧。。。

1、首先准备对应的架包

2、看看项目的架构

3、基本的web.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <display-name>shiro</display-name>

<!-- 加载springmvc -->
<servlet>
<servlet-name>SpringMVC</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:mvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>

<!-- 以.htm结尾的都被mvc拦截 -->
<servlet-mapping>
<servlet-name>SpringMVC</servlet-name>
<url-pattern>*.htm</url-pattern>
</servlet-mapping>

<!-- 启动spring 加载   需要加载其他的spring时 需启动该监听器
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
-->
</web-app>

3、配置classpath下的mvc.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"> <mvc:annotation-driven />
<!-- 自动扫描包 -->
<context:component-scan base-package="com.cat.spring.controller" />

<!--  配置mvc的拦截器 可以配置多个 -->
<mvc:interceptors>
<mvc:interceptor>
<!--  需要被拦截的路径 -->
<mvc:mapping path="/member/**" />
<!-- 拦截处理的interceptor -->
<bean class="com.cat.interceptor.MemberInterceptor" />
</mvc:interceptor>
</mvc:interceptors>

<!-- mvc返回页面的配置 -->
<bean id="viewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<!-- 模板路径为WEB-INF/pages/ -->
<property name="prefix">
<value>/WEB-INF/pages/</value>
</property>
<!-- 视图模板后缀为.JSP -->
<property name="suffix">
<value>.jsp</value>
</property>
</bean>

</beans>

4、接着就要配置拦截器了MemberInterceptor.java

/**
*
*/
package com.cat.interceptor;

import java.net.URLEncoder;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.commons.lang.StringUtils;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

/**
* @author chenlf
*
*         2014-3-25
*/
public class MemberInterceptor implements HandlerInterceptor {

public final static String SEESION_MEMBER = "seesion_member";

/*
* (non-Javadoc)
*
* @see org.springframework.web.servlet.HandlerInterceptor#afterCompletion(javax.servlet.http.HttpServletRequest,
* javax.servlet.http.HttpServletResponse, java.lang.Object, java.lang.Exception)
*/
public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2,
Exception arg3) throws Exception {
// TODO Auto-generated method stub

}

/*
* (non-Javadoc)
*
* @see org.springframework.web.servlet.HandlerInterceptor#postHandle(javax.servlet.http.HttpServletRequest,
* javax.servlet.http.HttpServletResponse, java.lang.Object, org.springframework.web.servlet.ModelAndView)
*/
public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2,
ModelAndView arg3) throws Exception {
// TODO Auto-generated method stub

}

/*
* (non-Javadoc)
* 拦截mvc.xml配置的/member/**路径的请求
* @see org.springframework.web.servlet.HandlerInterceptor#preHandle(javax.servlet.http.HttpServletRequest,
* javax.servlet.http.HttpServletResponse, java.lang.Object)
*/
public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
Object handler) throws Exception {
//请求的路径
String contextPath=request.getContextPath();
String	url=request.getServletPath().toString();
HttpSession session = request.getSession();
String user = (String) session.getAttribute(SEESION_MEMBER);
//这里可以根据session的用户来判断角色的权限，根据权限来重定向不同的页面，简单起见，这里只是做了一个重定向
if (StringUtils.isEmpty(user)) {
//被拦截，重定向到login界面
response.sendRedirect(contextPath+"/login.htm?redirectURL="
+ URLEncoder.encode(url));
return false;
}
return true;
}

}

这样拦截器的核心就配置完了，接下来就是一些登陆的处理操作

5、LoginController.java文件

/**
*
*/
package com.cat.spring.controller;

import java.net.URLDecoder;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.apache.commons.lang.StringUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

import com.cat.interceptor.MemberInterceptor;

/**
* @author chenlf
*
*         2014-3-24
*/
@Controller
public class LoginController {

@RequestMapping(value = "/login", method = RequestMethod.GET)
public ModelAndView login(String redirectURL, HttpServletRequest request) {
ModelAndView view = new ModelAndView();
//把拦截前路径存下来，以便登入成功可以直接请求到登录前的页面
view.addObject("redirectURL", redirectURL);
view.setViewName("/login");
return view;
}

@RequestMapping(value = "/submit", method = RequestMethod.POST)
public String submit(String username, String password, String redirectURL,
HttpServletRequest request) {
//模拟登陆成功 用户admin 密码admin的用户
if (StringUtils.isNotBlank(username) && StringUtils.isNotBlank(password)
&& username.equals("admin") && password.equals("admin")) {
//当登陆成功是，将用户信息存放到session中去
HttpSession session = request.getSession();
session.setAttribute(MemberInterceptor.SEESION_MEMBER, "admin");
if (StringUtils.isNotBlank(redirectURL)) {
return "redirect:" + URLDecoder.decode(redirectURL);
}
return "redirect:/member/index.htm";
} else {
if (StringUtils.isNotBlank(redirectURL)) {
return "redirect:/login.htm?" + URLDecoder.decode(redirectURL);
}
return "redirect:/login.htm";
}
}
}

6、下面就是login.jsp文件

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>mvc权限登陆login</title>
</head>
<body>
<h3>
mvc权限登陆login
</h3>
<form action="submit.htm" method="post">
<!-- 记录重定向的url -->
<input type="hidden" name="redirectURL" value="${redirectURL}" />
<table>
<tr>
<td>
账号
</td>
<td>
<input type="text" name="username" />
</td>
<td>
密码
</td>
<td>
<input type="password" name="password" />
</td>
</tr>
<tr>
<td colspan="2" align="center">
<input type="submit" value="提交" />
</td>
</tr>
</table>
</form>
</body>
</html>

7、剩下的就是一些正常的mvc请求处理的文件，这里就不赘诉了

8、到这里看看效果吧

a、当非登陆状态的时候，请求localhost:8010/demo-mvc/member/list.htm时，被拦截拦截，重定向到login页面，并携带了当前的这个路径（/member/list.htm）作为参数传到页面



b、输入正确的用户名admin 密码admin后登陆，会跳转到拦截前的页面



c、当登陆完成后，输入地址为http://localhost:8010/demo-mvc/member/index.htm，session中记录着当前用户的信息，不需要重新登陆了

9、因为篇幅问题，一些不重要的文件没有一一贴出来，有需要的可以到http://download.csdn.net/detail/a124753561/7098925下载源代码。