细说shiro之自定义filter

编程随笔

发布于 2019-09-11 16:06:51

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发布于 2019-09-11 16:06:51

文章被收录于专栏：后端开发随笔

写在前面

我们知道，shiro框架在Java Web应用中使用时，本质上是通过filter方式集成的。也就是说，它是遵循过滤器链规则的：filter的执行顺序与在web.xml中定义的顺序一致，如下所示：

<filter>
    <filter-name>securityFilter</filter-name>
    <filter-class>com.lenovo.iot.devicemanager.filter.SecurityFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>securityFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

<!-- The filter-name matches name of a 'shiroFilter' bean inside applicationContext.xml -->
<filter>
    <filter-name>shiroFilter</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
    <init-param>
        <param-name>targetFilterLifecycle</param-name>
        <param-value>true</param-value>
    </init-param>
</filter>

<!-- Make sure any request you want accessible to Shiro is filtered. /* catches all -->
<!-- requests.  Usually this filter mapping is defined first (before all others) to -->
<!-- ensure that Shiro works in subsequent filters in the filter chain:             -->
<filter-mapping>
    <filter-name>shiroFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

显然，securityFilter定义在shiroFilter之前，那么securityFilter也是在shiroFilter之前被访问到。根据这个原理，我们可以根据实际情况对shiro的filter进行扩展。举个例子，shiro默认的org.apache.shiro.web.filter.authc.UserFilter会对请求进行过滤，在未登录时请求会被重定向到登录页面。但是在API项目中，响应都是json格式，并不存在登录页面，此时就会返回404错误。

项目实践

在最新的项目中，前后端完全分离，通过API方式进行数据交换，并且在服务端集成了shiro进行权限控制，后端项目架构为：SpringMVC + Shiro。为了在拦截那些未执行登录的请求时返回json格式的响应，对org.apache.shiro.web.filter.authc.UserFilter进行了扩展。具体来说需要做2件事情： 1.扩展org.apache.shiro.web.filter.authc.UserFilter实现

public class ShiroUserFilter extends UserFilter {
    private static final Logger logger = LoggerFactory.getLogger(ShiroUserFilter.class);

    @Override
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        if(logger.isErrorEnabled()) {
            logger.error("account need login for: {}",  ((HttpServletRequest)request).getServletPath());
        }

        // 请求被拦截后直接返回json格式的响应数据
        response.getWriter().write(JsonResp.getJsonRespError(JsonResp.SC_NOT_LOGINED, "account not logined").toString());
        response.getWriter().flush();
        response.getWriter().close();
        return false;
    }
}

2.在spring中定义并使用自定义扩展的filter

<bean id="shiroFilter" class="org.apache.shiro.spring.web.ShiroFilterFactoryBean">
    <property name="securityManager" ref="securityManager"/>
    <property name="filters">
        <util:map>
            <entry key="shiroUserFilter" value-ref="shiroUserFilter" />
        </util:map>
    </property>
    <property name="filterChainDefinitions">
        <value>
            # some example chain definitions:
            # /admin/** = authc, roles[admin]
            # /docs/** = authc, perms[document:read]
            /**/login.do = anon
            /** = shiroUserFilter
            # more URL-to-FilterChain definitions here
        </value>
    </property>
</bean>

<!-- 定义扩展的filter实例 -->
<bean id="shiroUserFilter" class="com.lenovo.iot.devicemanager.filter.ShiroUserFilter" />

【参考】 https://shiro.apache.org/web.html#Web-FilterChainDefinitions

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原始发表：2017-11-16 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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