Shiro源码(一)-启动原理

0. 核心概念

Shiro 的架构图如下:

几个核心概念如下:

subject:主体,可以是用户也可以是程序,主体要访问系统,系统需要对主体进行认证、授权。

securityManager:安全管理器,主体进行认证和授权都 是通过securityManager进行。

authenticator:认证器,主体进行认证最终通过authenticator进行的。 Authentication - 认证(也就是验证身份合法性)

authorizer:授权器,主体进行授权最终通过authorizer进行的。Authorization - 鉴权(也就是判断是否有相应的权限)

sessionManager:web应用中一般是用web容器对session进行管理,shiro也提供一套session管理的方式。

SessionDao: 通过SessionDao管理session数据,针对个性化的session数据存储需要使用sessionDao。

cache Manager:缓存管理器,主要对session和授权数据进行缓存,比如将授权数据通过cacheManager进行缓存管理,和ehcache整合对缓存数据进行管理。

realm:域,领域,相当于数据源,通过realm存取认证、授权相关数据。注意:在realm中存储授权和认证的逻辑。

1. 自动配置

1. pom 引入如下配置:

        <dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-spring</artifactId>
            <version>1.5.3</version>
        </dependency>

2. 自定义Realm

import com.zd.bx.bean.user.User;
import com.zd.bx.service.user.TokenService;
import com.zd.bx.utils.permission.PermissionUtils;
import com.zd.bx.utils.shiro.Token;
import com.zd.bx.utils.system.SpringBootUtils;
import org.apache.shiro.SecurityUtils;
import org.apache.shiro.authc.*;
import org.apache.shiro.authz.AuthorizationInfo;
import org.apache.shiro.authz.SimpleAuthorizationInfo;
import org.apache.shiro.realm.AuthorizingRealm;
import org.apache.shiro.subject.PrincipalCollection;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class CustomRealm extends AuthorizingRealm {

    private static final Logger log = LoggerFactory.getLogger(CustomRealm.class);

    /**
     * 鉴权
     *
     * @param principalCollection
     * @return
     */
    @Override
    protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principalCollection) {
        // getPrimaryPrincipal获取到的是doGetAuthenticationInfo方法最后存进去的user对象
        Object primaryPrincipal = principalCollection.getPrimaryPrincipal();
        if (primaryPrincipal == null) {
            return null;
        }

        SimpleAuthorizationInfo authorizationInfo = new SimpleAuthorizationInfo();
        User currentUser = (User) primaryPrincipal;
        // 添加角色
        authorizationInfo.addRoles(PermissionUtils.listUserRolenames(currentUser));
        // 添加权限
        authorizationInfo.addStringPermissions(PermissionUtils.listUserPermissionCodes(currentUser));

        log.debug("authorizationInfo roles: {}, permissions: {}", authorizationInfo.getRoles(),
                authorizationInfo.getStringPermissions());
        return authorizationInfo;
    }

    /**
     * 认证
     */
    @Override
    protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken authenticationToken)
            throws AuthenticationException {

        if (authenticationToken == null) {
            throw new IncorrectCredentialsException("token失效,请重新登录");
        }

        Token token = (Token) authenticationToken;
        TokenService tokenService = SpringBootUtils.getBean(TokenService.class);
        User user = tokenService.getUser(token);
        return new SimpleAuthenticationInfo(user, token.getCredentials(), this.getName());
    }

    // 清除缓存
    public void clearCache() {
        PrincipalCollection principalCollection = SecurityUtils.getSubject().getPrincipals();
        super.clearCache(principalCollection);
    }
}

3. 编写Configuration 配置文件注入相关bean 到Spring 中

import com.zd.bx.utils.file.PropertiesFileUtils;
import org.apache.commons.collections4.CollectionUtils;
import org.apache.shiro.mgt.SecurityManager;
import org.apache.shiro.spring.web.ShiroFilterFactoryBean;
import org.apache.shiro.web.mgt.DefaultWebSecurityManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;

@Configuration
public class ShiroConfig {

    private static final Map<String, String> FILTER_CHAIN_DEFINITION_MAP = new HashMap<>();

    static {
        initFilterChainDefinitionMap();
    }

    private static void initFilterChainDefinitionMap() {
        // 加载配置在permission.properties文件中的配置
        Properties properties = PropertiesFileUtils.getProperties("permission.properties");
        if (properties != null && CollectionUtils.isNotEmpty(properties.entrySet())) {
            Iterator<Entry<Object, Object>> iterator = properties.entrySet().iterator();
            while (iterator.hasNext()) {
                Entry<Object, Object> next = iterator.next();
                String key = next.getKey().toString();
                String value = next.getValue().toString();
                FILTER_CHAIN_DEFINITION_MAP.put(key, value);
            }
        }

        /**
         *  路径 -> 过滤器名称1[参数1,参数2,参数3...],过滤器名称2[参数1,参数2...]...
         * 自定义配置(前面是路径, 后面是具体的过滤器名称加参数,多个用逗号进行分割,过滤器参数也多个之间也是用逗号分割))
         * 有的过滤器不需要参数,比如anon, authc, shiro 在解析的时候接默认解析一个数组为 [name, null]
         */
        FILTER_CHAIN_DEFINITION_MAP.put("/test2", "anon"); // 测试地址
        FILTER_CHAIN_DEFINITION_MAP.put("/user/**", "roles[系统管理员,用户管理员],perms['user:manager:*']");
        FILTER_CHAIN_DEFINITION_MAP.put("/**", "authc"); // 所有资源都需要经过验证
    }

    // 将自己的验证方式加入容器
    @Bean
    public CustomRealm myShiroRealm() {
        CustomRealm customRealm = new CustomRealm();
        return customRealm;
    }

    // 权限管理,配置主要是Realm的管理认证
    @Bean
    public SecurityManager securityManager() {
        DefaultWebSecurityManager securityManager = new DefaultWebSecurityManager();
        securityManager.setRealm(myShiroRealm());
        return securityManager;
    }

    // Filter工厂,设置对应的过滤条件和跳转条件
    @Bean
    public ShiroFilterFactoryBean shiroFilterFactoryBean(SecurityManager securityManager) {
        ShiroFilterFactoryBean shiroFilterFactoryBean = new ShiroFilterFactoryBean();
        shiroFilterFactoryBean.setSecurityManager(securityManager);

        // 登录页和成功跳转页面不需要设置(前后端不分离项目可以写)
        // factoryBean.setLoginUrl("/shiro/login.html");
        // factoryBean.setSuccessUrl("/shiro/index.html");

        // 自定义需要权限验证的过滤器。对于前后端分离的项目可以自定重写这个filter
//        Map<String, Filter> filterMaps = new HashMap<>();
//        filterMaps.put("authc", new ShiroAuthFilter());
//        shiroFilterFactoryBean.setFilters(filterMaps);

        // 定义处理规则
        shiroFilterFactoryBean.setFilterChainDefinitionMap(setFilterChainDefinitionMap());

        return shiroFilterFactoryBean;
    }

    private Map<String, String> setFilterChainDefinitionMap() {
        return FILTER_CHAIN_DEFINITION_MAP;
    }
}

4. 编写测试Controller

import com.zd.bx.bean.user.Permission;
import com.zd.bx.service.user.PermissionService;
import org.apache.shiro.authz.annotation.RequiresPermissions;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestController {

    @RequiresPermissions(value = {"test"})
    @GetMapping("/test")
    public String test() {
        return "test";
    }

    @Autowired
    private PermissionService permissionService;

    @GetMapping("/test2")
    public String test2() {
        Permission permissions = permissionService.selectByUniqueCode("2aeb7756-62f7-49ba-aa41-31e1bbc87040");
        Permission permissions2 = permissionService.selectByUniqueCode("2aeb7756-62f7-49ba-aa41-31e1bbc87040");
        int i = permissionService.selectCount(null);
        System.out.println(permissions);
        System.out.println(permissions2);
        System.out.println(i);
        return "test";
    }
}

5. 测试

(1) 测试可以匿名访问的连接:

$ curl http://localhost:8081/test2
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100     4  100     4    0     0    129      0 --:--:-- --:--:-- --:--:--   137test

(2) 访问需要鉴权的连接 /test

页面会被重定向到:/login.jsp

  如果想设置登录页面、未授权页面、登录成功页面, 可以通过上面 ShiroFilterFactoryBean 进行设置。 到这里基本的功能可以使用。下面研究其执行原理。

2. 源码剖析

  我们在Configuration 中注入的对象有三个CustomRealm、SecurityManager、ShiroFilterFactoryBean。 前面两个对象可以说是shiro必须的组件,realm 注入到Securitymanager 中; SecurityManager 注入到了 ShiroFilterFactoryBean 中。

1. SecurityManager 内部包含的相关属性

如下代码:

    @Bean
    public SecurityManager securityManager() {
        DefaultWebSecurityManager securityManager = new DefaultWebSecurityManager();
        securityManager.setRealm(myShiroRealm());
        return securityManager;
    }

1》这里设置了一个自定义的Realm,也可以调用 setRealms 设置多个Realm.

2》DefaultWebSecurityManager 构造查看

其继承关系如下:

1》  从CachingSecurityManager 开始查看其内部重要属性以及方法:

public abstract class CachingSecurityManager implements SecurityManager, Destroyable, CacheManagerAware, EventBusAware {
    private CacheManager cacheManager;
    private EventBus eventBus;

  这里有缓存管理器相关。

2》RealmSecurityManager

public abstract class RealmSecurityManager extends CachingSecurityManager {
    private Collection<Realm> realms;

    public RealmSecurityManager() {
    }

    public void setRealm(Realm realm) {
        if (realm == null) {
            throw new IllegalArgumentException("Realm argument cannot be null");
        } else {
            Collection<Realm> realms = new ArrayList(1);
            realms.add(realm);
            this.setRealms(realms);
        }
    }

    public void setRealms(Collection<Realm> realms) {
        if (realms == null) {
            throw new IllegalArgumentException("Realms collection argument cannot be null.");
        } else if (realms.isEmpty()) {
            throw new IllegalArgumentException("Realms collection argument cannot be empty.");
        } else {
            this.realms = realms;
            this.afterRealmsSet();
        }
    }

   有设置Realm 相关的API

3》 org.apache.shiro.mgt.AuthenticatingSecurityManager

public abstract class AuthenticatingSecurityManager extends RealmSecurityManager {
    private Authenticator authenticator = new ModularRealmAuthenticator();

   包含一个默认的认证器。

4》org.apache.shiro.mgt.AuthorizingSecurityManager

public abstract class AuthorizingSecurityManager extends AuthenticatingSecurityManager {
    private Authorizer authorizer = new ModularRealmAuthorizer();

  包含一个默认的鉴权器

5》org.apache.shiro.mgt.SessionsSecurityManager

public abstract class SessionsSecurityManager extends AuthorizingSecurityManager {
    private SessionManager sessionManager = new DefaultSessionManager();

  包含一个默认的session 管理器

6》 org.apache.shiro.mgt.DefaultSecurityManager

public class DefaultSecurityManager extends SessionsSecurityManager {
    private static final Logger log = LoggerFactory.getLogger(DefaultSecurityManager.class);
    protected RememberMeManager rememberMeManager;
    protected SubjectDAO subjectDAO;
    protected SubjectFactory subjectFactory;

    public DefaultSecurityManager() {
        this.subjectFactory = new DefaultSubjectFactory();
        this.subjectDAO = new DefaultSubjectDAO();
    }

    public DefaultSecurityManager(Realm singleRealm) {
        this();
        this.setRealm(singleRealm);
    }

    public DefaultSecurityManager(Collection<Realm> realms) {
        this();
        this.setRealms(realms);
    }

  包含两个重要属性:RememberMeManager、 SubjectFactory

7》 org.apache.shiro.web.mgt.DefaultWebSecurityManager#DefaultWebSecurityManager

    public DefaultWebSecurityManager() {
        super();
        DefaultWebSessionStorageEvaluator webEvalutator = new DefaultWebSessionStorageEvaluator();  
        ((DefaultSubjectDAO) this.subjectDAO).setSessionStorageEvaluator(webEvalutator);
        this.sessionMode = HTTP_SESSION_MODE;
        setSubjectFactory(new DefaultWebSubjectFactory());
        setRememberMeManager(new CookieRememberMeManager());
        setSessionManager(new ServletContainerSessionManager());
        webEvalutator.setSessionManager(getSessionManager());
    }

  从上面的继承链可以看到我们的SecurityManager 通过一系列的继承可以具有: cache管理、realm管理器、认证器、鉴权器、session 管理器等重要功能。

2. ShiroFilterFactoryBean 查看

  可以看到这个类是一个FactoryBean, 其注入到Spring 内部的是getOabject 返回的对象。

org.apache.shiro.spring.web.ShiroFilterFactoryBean 源码如下:

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.shiro.spring.web;

import org.apache.shiro.config.Ini;
import org.apache.shiro.mgt.SecurityManager;
import org.apache.shiro.util.CollectionUtils;
import org.apache.shiro.util.Nameable;
import org.apache.shiro.util.StringUtils;
import org.apache.shiro.web.config.IniFilterChainResolverFactory;
import org.apache.shiro.web.filter.AccessControlFilter;
import org.apache.shiro.web.filter.authc.AuthenticationFilter;
import org.apache.shiro.web.filter.authz.AuthorizationFilter;
import org.apache.shiro.web.filter.mgt.DefaultFilterChainManager;
import org.apache.shiro.web.filter.mgt.FilterChainManager;
import org.apache.shiro.web.filter.mgt.FilterChainResolver;
import org.apache.shiro.web.filter.mgt.PathMatchingFilterChainResolver;
import org.apache.shiro.web.mgt.WebSecurityManager;
import org.apache.shiro.web.servlet.AbstractShiroFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanInitializationException;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.config.BeanPostProcessor;

import javax.servlet.Filter;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * {@link org.springframework.beans.factory.FactoryBean FactoryBean} to be used in Spring-based web applications for
 * defining the master Shiro Filter.
 * <h4>Usage</h4>
 * Declare a DelegatingFilterProxy in {@code web.xml}, matching the filter name to the bean id:
 * <pre>
 * &lt;filter&gt;
 *   &lt;filter-name&gt;<b>shiroFilter</b>&lt;/filter-name&gt;
 *   &lt;filter-class&gt;org.springframework.web.filter.DelegatingFilterProxy&lt;filter-class&gt;
 *   &lt;init-param&gt;
 *    &lt;param-name&gt;targetFilterLifecycle&lt;/param-name&gt;
 *     &lt;param-value&gt;true&lt;/param-value&gt;
 *   &lt;/init-param&gt;
 * &lt;/filter&gt;
 * </pre>
 * Then, in your spring XML file that defines your web ApplicationContext:
 * <pre>
 * &lt;bean id="<b>shiroFilter</b>" class="org.apache.shiro.spring.web.ShiroFilterFactoryBean"&gt;
 *    &lt;property name="securityManager" ref="securityManager"/&gt;
 *    &lt;!-- other properties as necessary ... --&gt;
 * &lt;/bean&gt;
 * </pre>
 * <h4>Filter Auto-Discovery</h4>
 * While there is a {@link #setFilters(java.util.Map) filters} property that allows you to assign a filter beans
 * to the 'pool' of filters available when defining {@link #setFilterChainDefinitions(String) filter chains}, it is
 * optional.
 * <p/>
 * This implementation is also a {@link BeanPostProcessor} and will acquire
 * any {@link javax.servlet.Filter Filter} beans defined independently in your Spring application context.  Upon
 * discovery, they will be automatically added to the {@link #setFilters(java.util.Map) map} keyed by the bean ID.
 * That ID can then be used in the filter chain definitions, for example:
 *
 * <pre>
 * &lt;bean id="<b>myCustomFilter</b>" class="com.class.that.implements.javax.servlet.Filter"/&gt;
 * ...
 * &lt;bean id="shiroFilter" class="org.apache.shiro.spring.web.ShiroFilterFactoryBean"&gt;
 *    ...
 *    &lt;property name="filterChainDefinitions"&gt;
 *        &lt;value&gt;
 *            /some/path/** = authc, <b>myCustomFilter</b>
 *        &lt;/value&gt;
 *    &lt;/property&gt;
 * &lt;/bean&gt;
 * </pre>
 * <h4>Global Property Values</h4>
 * Most Shiro servlet Filter implementations exist for defining custom Filter
 * {@link #setFilterChainDefinitions(String) chain definitions}.  Most implementations subclass one of the
 * {@link AccessControlFilter}, {@link AuthenticationFilter}, {@link AuthorizationFilter} classes to simplify things,
 * and each of these 3 classes has configurable properties that are application-specific.
 * <p/>
 * A dilemma arises where, if you want to for example set the application's 'loginUrl' for any Filter, you don't want
 * to have to manually specify that value for <em>each</em> filter instance definied.
 * <p/>
 * To prevent configuration duplication, this implementation provides the following properties to allow you
 * to set relevant values in only one place:
 * <ul>
 * <li>{@link #setLoginUrl(String)}</li>
 * <li>{@link #setSuccessUrl(String)}</li>
 * <li>{@link #setUnauthorizedUrl(String)}</li>
 * </ul>
 *
 * Then at startup, any values specified via these 3 properties will be applied to all configured
 * Filter instances so you don't have to specify them individually on each filter instance.  To ensure your own custom
 * filters benefit from this convenience, your filter implementation should subclass one of the 3 mentioned
 * earlier.
 *
 * @see org.springframework.web.filter.DelegatingFilterProxy DelegatingFilterProxy
 * @since 1.0
 */
public class ShiroFilterFactoryBean implements FactoryBean, BeanPostProcessor {

    private static transient final Logger log = LoggerFactory.getLogger(ShiroFilterFactoryBean.class);

    private SecurityManager securityManager;

    private Map<String, Filter> filters;

    private Map<String, String> filterChainDefinitionMap; //urlPathExpression_to_comma-delimited-filter-chain-definition

    private String loginUrl;
    private String successUrl;
    private String unauthorizedUrl;

    private AbstractShiroFilter instance;

    public ShiroFilterFactoryBean() {
        this.filters = new LinkedHashMap<String, Filter>();
        this.filterChainDefinitionMap = new LinkedHashMap<String, String>(); //order matters!
    }

    /**
     * Sets the application {@code SecurityManager} instance to be used by the constructed Shiro Filter.  This is a
     * required property - failure to set it will throw an initialization exception.
     *
     * @return the application {@code SecurityManager} instance to be used by the constructed Shiro Filter.
     */
    public SecurityManager getSecurityManager() {
        return securityManager;
    }

    /**
     * Sets the application {@code SecurityManager} instance to be used by the constructed Shiro Filter.  This is a
     * required property - failure to set it will throw an initialization exception.
     *
     * @param securityManager the application {@code SecurityManager} instance to be used by the constructed Shiro Filter.
     */
    public void setSecurityManager(SecurityManager securityManager) {
        this.securityManager = securityManager;
    }

    /**
     * Returns the application's login URL to be assigned to all acquired Filters that subclass
     * {@link AccessControlFilter} or {@code null} if no value should be assigned globally. The default value
     * is {@code null}.
     *
     * @return the application's login URL to be assigned to all acquired Filters that subclass
     *         {@link AccessControlFilter} or {@code null} if no value should be assigned globally.
     * @see #setLoginUrl
     */
    public String getLoginUrl() {
        return loginUrl;
    }

    /**
     * Sets the application's login URL to be assigned to all acquired Filters that subclass
     * {@link AccessControlFilter}.  This is a convenience mechanism: for all configured {@link #setFilters filters},
     * as well for any default ones ({@code authc}, {@code user}, etc), this value will be passed on to each Filter
     * via the {@link AccessControlFilter#setLoginUrl(String)} method<b>*</b>.  This eliminates the need to
     * configure the 'loginUrl' property manually on each filter instance, and instead that can be configured once
     * via this attribute.
     * <p/>
     * <b>*</b>If a filter already has already been explicitly configured with a value, it will
     * <em>not</em> receive this value. Individual filter configuration overrides this global convenience property.
     *
     * @param loginUrl the application's login URL to apply to as a convenience to all discovered
     *                 {@link AccessControlFilter} instances.
     * @see AccessControlFilter#setLoginUrl(String)
     */
    public void setLoginUrl(String loginUrl) {
        this.loginUrl = loginUrl;
    }

    /**
     * Returns the application's after-login success URL to be assigned to all acquired Filters that subclass
     * {@link AuthenticationFilter} or {@code null} if no value should be assigned globally. The default value
     * is {@code null}.
     *
     * @return the application's after-login success URL to be assigned to all acquired Filters that subclass
     *         {@link AuthenticationFilter} or {@code null} if no value should be assigned globally.
     * @see #setSuccessUrl
     */
    public String getSuccessUrl() {
        return successUrl;
    }

    /**
     * Sets the application's after-login success URL to be assigned to all acquired Filters that subclass
     * {@link AuthenticationFilter}.  This is a convenience mechanism: for all configured {@link #setFilters filters},
     * as well for any default ones ({@code authc}, {@code user}, etc), this value will be passed on to each Filter
     * via the {@link AuthenticationFilter#setSuccessUrl(String)} method<b>*</b>.  This eliminates the need to
     * configure the 'successUrl' property manually on each filter instance, and instead that can be configured once
     * via this attribute.
     * <p/>
     * <b>*</b>If a filter already has already been explicitly configured with a value, it will
     * <em>not</em> receive this value. Individual filter configuration overrides this global convenience property.
     *
     * @param successUrl the application's after-login success URL to apply to as a convenience to all discovered
     *                   {@link AccessControlFilter} instances.
     * @see AuthenticationFilter#setSuccessUrl(String)
     */
    public void setSuccessUrl(String successUrl) {
        this.successUrl = successUrl;
    }

    /**
     * Returns the application's after-login success URL to be assigned to all acquired Filters that subclass
     * {@link AuthenticationFilter} or {@code null} if no value should be assigned globally. The default value
     * is {@code null}.
     *
     * @return the application's after-login success URL to be assigned to all acquired Filters that subclass
     *         {@link AuthenticationFilter} or {@code null} if no value should be assigned globally.
     * @see #setSuccessUrl
     */
    public String getUnauthorizedUrl() {
        return unauthorizedUrl;
    }

    /**
     * Sets the application's 'unauthorized' URL to be assigned to all acquired Filters that subclass
     * {@link AuthorizationFilter}.  This is a convenience mechanism: for all configured {@link #setFilters filters},
     * as well for any default ones ({@code roles}, {@code perms}, etc), this value will be passed on to each Filter
     * via the {@link AuthorizationFilter#setUnauthorizedUrl(String)} method<b>*</b>.  This eliminates the need to
     * configure the 'unauthorizedUrl' property manually on each filter instance, and instead that can be configured once
     * via this attribute.
     * <p/>
     * <b>*</b>If a filter already has already been explicitly configured with a value, it will
     * <em>not</em> receive this value. Individual filter configuration overrides this global convenience property.
     *
     * @param unauthorizedUrl the application's 'unauthorized' URL to apply to as a convenience to all discovered
     *                        {@link AuthorizationFilter} instances.
     * @see AuthorizationFilter#setUnauthorizedUrl(String)
     */
    public void setUnauthorizedUrl(String unauthorizedUrl) {
        this.unauthorizedUrl = unauthorizedUrl;
    }

    /**
     * Returns the filterName-to-Filter map of filters available for reference when defining filter chain definitions.
     * All filter chain definitions will reference filters by the names in this map (i.e. the keys).
     *
     * @return the filterName-to-Filter map of filters available for reference when defining filter chain definitions.
     */
    public Map<String, Filter> getFilters() {
        return filters;
    }

    /**
     * Sets the filterName-to-Filter map of filters available for reference when creating
     * {@link #setFilterChainDefinitionMap(java.util.Map) filter chain definitions}.
     * <p/>
     * <b>Note:</b> This property is optional:  this {@code FactoryBean} implementation will discover all beans in the
     * web application context that implement the {@link Filter} interface and automatically add them to this filter
     * map under their bean name.
     * <p/>
     * For example, just defining this bean in a web Spring XML application context:
     * <pre>
     * &lt;bean id=&quot;myFilter&quot; class=&quot;com.class.that.implements.javax.servlet.Filter&quot;&gt;
     * ...
     * &lt;/bean&gt;</pre>
     * Will automatically place that bean into this Filters map under the key '<b>myFilter</b>'.
     *
     * @param filters the optional filterName-to-Filter map of filters available for reference when creating
     *                {@link #setFilterChainDefinitionMap (java.util.Map) filter chain definitions}.
     */
    public void setFilters(Map<String, Filter> filters) {
        this.filters = filters;
    }

    /**
     * Returns the chainName-to-chainDefinition map of chain definitions to use for creating filter chains intercepted
     * by the Shiro Filter.  Each map entry should conform to the format defined by the
     * {@link FilterChainManager#createChain(String, String)} JavaDoc, where the map key is the chain name (e.g. URL
     * path expression) and the map value is the comma-delimited string chain definition.
     *
     * @return he chainName-to-chainDefinition map of chain definitions to use for creating filter chains intercepted
     *         by the Shiro Filter.
     */
    public Map<String, String> getFilterChainDefinitionMap() {
        return filterChainDefinitionMap;
    }

    /**
     * Sets the chainName-to-chainDefinition map of chain definitions to use for creating filter chains intercepted
     * by the Shiro Filter.  Each map entry should conform to the format defined by the
     * {@link FilterChainManager#createChain(String, String)} JavaDoc, where the map key is the chain name (e.g. URL
     * path expression) and the map value is the comma-delimited string chain definition.
     *
     * @param filterChainDefinitionMap the chainName-to-chainDefinition map of chain definitions to use for creating
     *                                 filter chains intercepted by the Shiro Filter.
     */
    public void setFilterChainDefinitionMap(Map<String, String> filterChainDefinitionMap) {
        this.filterChainDefinitionMap = filterChainDefinitionMap;
    }

    /**
     * A convenience method that sets the {@link #setFilterChainDefinitionMap(java.util.Map) filterChainDefinitionMap}
     * property by accepting a {@link java.util.Properties Properties}-compatible string (multi-line key/value pairs).
     * Each key/value pair must conform to the format defined by the
     * {@link FilterChainManager#createChain(String,String)} JavaDoc - each property key is an ant URL
     * path expression and the value is the comma-delimited chain definition.
     *
     * @param definitions a {@link java.util.Properties Properties}-compatible string (multi-line key/value pairs)
     *                    where each key/value pair represents a single urlPathExpression-commaDelimitedChainDefinition.
     */
    public void setFilterChainDefinitions(String definitions) {
        Ini ini = new Ini();
        ini.load(definitions);
        //did they explicitly state a 'urls' section?  Not necessary, but just in case:
        Ini.Section section = ini.getSection(IniFilterChainResolverFactory.URLS);
        if (CollectionUtils.isEmpty(section)) {
            //no urls section.  Since this _is_ a urls chain definition property, just assume the
            //default section contains only the definitions:
            section = ini.getSection(Ini.DEFAULT_SECTION_NAME);
        }
        setFilterChainDefinitionMap(section);
    }

    /**
     * Lazily creates and returns a {@link AbstractShiroFilter} concrete instance via the
     * {@link #createInstance} method.
     *
     * @return the application's Shiro Filter instance used to filter incoming web requests.
     * @throws Exception if there is a problem creating the {@code Filter} instance.
     */
    public Object getObject() throws Exception {
        if (instance == null) {
            instance = createInstance();
        }
        return instance;
    }

    /**
     * Returns <code>{@link org.apache.shiro.web.servlet.AbstractShiroFilter}.class</code>
     *
     * @return <code>{@link org.apache.shiro.web.servlet.AbstractShiroFilter}.class</code>
     */
    public Class getObjectType() {
        return SpringShiroFilter.class;
    }

    /**
     * Returns {@code true} always.  There is almost always only ever 1 Shiro {@code Filter} per web application.
     *
     * @return {@code true} always.  There is almost always only ever 1 Shiro {@code Filter} per web application.
     */
    public boolean isSingleton() {
        return true;
    }

    protected FilterChainManager createFilterChainManager() {

        DefaultFilterChainManager manager = new DefaultFilterChainManager();
        Map<String, Filter> defaultFilters = manager.getFilters();
        //apply global settings if necessary:
        for (Filter filter : defaultFilters.values()) {
            applyGlobalPropertiesIfNecessary(filter);
        }

        //Apply the acquired and/or configured filters:
        Map<String, Filter> filters = getFilters();
        if (!CollectionUtils.isEmpty(filters)) {
            for (Map.Entry<String, Filter> entry : filters.entrySet()) {
                String name = entry.getKey();
                Filter filter = entry.getValue();
                applyGlobalPropertiesIfNecessary(filter);
                if (filter instanceof Nameable) {
                    ((Nameable) filter).setName(name);
                }
                //'init' argument is false, since Spring-configured filters should be initialized
                //in Spring (i.e. 'init-method=blah') or implement InitializingBean:
                manager.addFilter(name, filter, false);
            }
        }

        //build up the chains:
        Map<String, String> chains = getFilterChainDefinitionMap();
        if (!CollectionUtils.isEmpty(chains)) {
            for (Map.Entry<String, String> entry : chains.entrySet()) {
                String url = entry.getKey();
                String chainDefinition = entry.getValue();
                manager.createChain(url, chainDefinition);
            }
        }

        return manager;
    }

    /**
     * This implementation:
     * <ol>
     * <li>Ensures the required {@link #setSecurityManager(org.apache.shiro.mgt.SecurityManager) securityManager}
     * property has been set</li>
     * <li>{@link #createFilterChainManager() Creates} a {@link FilterChainManager} instance that reflects the
     * configured {@link #setFilters(java.util.Map) filters} and
     * {@link #setFilterChainDefinitionMap(java.util.Map) filter chain definitions}</li>
     * <li>Wraps the FilterChainManager with a suitable
     * {@link org.apache.shiro.web.filter.mgt.FilterChainResolver FilterChainResolver} since the Shiro Filter
     * implementations do not know of {@code FilterChainManager}s</li>
     * <li>Sets both the {@code SecurityManager} and {@code FilterChainResolver} instances on a new Shiro Filter
     * instance and returns that filter instance.</li>
     * </ol>
     *
     * @return a new Shiro Filter reflecting any configured filters and filter chain definitions.
     * @throws Exception if there is a problem creating the AbstractShiroFilter instance.
     */
    protected AbstractShiroFilter createInstance() throws Exception {

        log.debug("Creating Shiro Filter instance.");

        SecurityManager securityManager = getSecurityManager();
        if (securityManager == null) {
            String msg = "SecurityManager property must be set.";
            throw new BeanInitializationException(msg);
        }

        if (!(securityManager instanceof WebSecurityManager)) {
            String msg = "The security manager does not implement the WebSecurityManager interface.";
            throw new BeanInitializationException(msg);
        }

        FilterChainManager manager = createFilterChainManager();

        //Expose the constructed FilterChainManager by first wrapping it in a
        // FilterChainResolver implementation. The AbstractShiroFilter implementations
        // do not know about FilterChainManagers - only resolvers:
        PathMatchingFilterChainResolver chainResolver = new PathMatchingFilterChainResolver();
        chainResolver.setFilterChainManager(manager);

        //Now create a concrete ShiroFilter instance and apply the acquired SecurityManager and built
        //FilterChainResolver.  It doesn't matter that the instance is an anonymous inner class
        //here - we're just using it because it is a concrete AbstractShiroFilter instance that accepts
        //injection of the SecurityManager and FilterChainResolver:
        return new SpringShiroFilter((WebSecurityManager) securityManager, chainResolver);
    }

    private void applyLoginUrlIfNecessary(Filter filter) {
        String loginUrl = getLoginUrl();
        if (StringUtils.hasText(loginUrl) && (filter instanceof AccessControlFilter)) {
            AccessControlFilter acFilter = (AccessControlFilter) filter;
            //only apply the login url if they haven't explicitly configured one already:
            String existingLoginUrl = acFilter.getLoginUrl();
            if (AccessControlFilter.DEFAULT_LOGIN_URL.equals(existingLoginUrl)) {
                acFilter.setLoginUrl(loginUrl);
            }
        }
    }

    private void applySuccessUrlIfNecessary(Filter filter) {
        String successUrl = getSuccessUrl();
        if (StringUtils.hasText(successUrl) && (filter instanceof AuthenticationFilter)) {
            AuthenticationFilter authcFilter = (AuthenticationFilter) filter;
            //only apply the successUrl if they haven't explicitly configured one already:
            String existingSuccessUrl = authcFilter.getSuccessUrl();
            if (AuthenticationFilter.DEFAULT_SUCCESS_URL.equals(existingSuccessUrl)) {
                authcFilter.setSuccessUrl(successUrl);
            }
        }
    }

    private void applyUnauthorizedUrlIfNecessary(Filter filter) {
        String unauthorizedUrl = getUnauthorizedUrl();
        if (StringUtils.hasText(unauthorizedUrl) && (filter instanceof AuthorizationFilter)) {
            AuthorizationFilter authzFilter = (AuthorizationFilter) filter;
            //only apply the unauthorizedUrl if they haven't explicitly configured one already:
            String existingUnauthorizedUrl = authzFilter.getUnauthorizedUrl();
            if (existingUnauthorizedUrl == null) {
                authzFilter.setUnauthorizedUrl(unauthorizedUrl);
            }
        }
    }

    private void applyGlobalPropertiesIfNecessary(Filter filter) {
        applyLoginUrlIfNecessary(filter);
        applySuccessUrlIfNecessary(filter);
        applyUnauthorizedUrlIfNecessary(filter);
    }

    /**
     * Inspects a bean, and if it implements the {@link Filter} interface, automatically adds that filter
     * instance to the internal {@link #setFilters(java.util.Map) filters map} that will be referenced
     * later during filter chain construction.
     */
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        if (bean instanceof Filter) {
            log.debug("Found filter chain candidate filter '{}'", beanName);
            Filter filter = (Filter) bean;
            applyGlobalPropertiesIfNecessary(filter);
            getFilters().put(beanName, filter);
        } else {
            log.trace("Ignoring non-Filter bean '{}'", beanName);
        }
        return bean;
    }

    /**
     * Does nothing - only exists to satisfy the BeanPostProcessor interface and immediately returns the
     * {@code bean} argument.
     */
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        return bean;
    }

    /**
     * Ordinarily the {@code AbstractShiroFilter} must be subclassed to additionally perform configuration
     * and initialization behavior.  Because this {@code FactoryBean} implementation manually builds the
     * {@link AbstractShiroFilter}'s
     * {@link AbstractShiroFilter#setSecurityManager(org.apache.shiro.web.mgt.WebSecurityManager) securityManager} and
     * {@link AbstractShiroFilter#setFilterChainResolver(org.apache.shiro.web.filter.mgt.FilterChainResolver) filterChainResolver}
     * properties, the only thing left to do is set those properties explicitly.  We do that in a simple
     * concrete subclass in the constructor.
     */
    private static final class SpringShiroFilter extends AbstractShiroFilter {

        protected SpringShiroFilter(WebSecurityManager webSecurityManager, FilterChainResolver resolver) {
            super();
            if (webSecurityManager == null) {
                throw new IllegalArgumentException("WebSecurityManager property cannot be null.");
            }
            setSecurityManager(webSecurityManager);
            if (resolver != null) {
                setFilterChainResolver(resolver);
            }
        }
    }
}
View Code

1. org.apache.shiro.spring.web.ShiroFilterFactoryBean#getObjectType 决定返回对象的类型:SpringShiroFilter。 SpringShiroFilter的继承关系如下:

   可以看到是一个javax.servlet.Filter, 也就是我们常说的filter。 既然是一个filter, 之前在Spring 动态注入filter 的过程中了解过。默认这种方式注入的filter,name 为bean的名称,拦截的url 默认为"/*", 也就是所有请求。

  这里也可以看出,shiro 发挥作用是从这个 SpringShiroFilter 开始的。

2. getObject 返回给Spring 的对象 org.apache.shiro.spring.web.ShiroFilterFactoryBean#createInstance 代码解读

(1)  获取到securityManager, 并对其进行验证,类型必须是 WebSecurityManager

(2)  调用 createFilterChainManager 创建 FilterChainManager, 这个对象是shiro 封装的自己内部过滤的责任链条。

    protected FilterChainManager createFilterChainManager() {

        DefaultFilterChainManager manager = new DefaultFilterChainManager();
        Map<String, Filter> defaultFilters = manager.getFilters();
        //apply global settings if necessary:
        for (Filter filter : defaultFilters.values()) {
            applyGlobalPropertiesIfNecessary(filter);
        }

        //Apply the acquired and/or configured filters:
        Map<String, Filter> filters = getFilters();
        if (!CollectionUtils.isEmpty(filters)) {
            for (Map.Entry<String, Filter> entry : filters.entrySet()) {
                String name = entry.getKey();
                Filter filter = entry.getValue();
                applyGlobalPropertiesIfNecessary(filter);
                if (filter instanceof Nameable) {
                    ((Nameable) filter).setName(name);
                }
                //'init' argument is false, since Spring-configured filters should be initialized
                //in Spring (i.e. 'init-method=blah') or implement InitializingBean:
                manager.addFilter(name, filter, false);
            }
        }

        //build up the chains:
        Map<String, String> chains = getFilterChainDefinitionMap();
        if (!CollectionUtils.isEmpty(chains)) {
            for (Map.Entry<String, String> entry : chains.entrySet()) {
                String url = entry.getKey();
                String chainDefinition = entry.getValue();
                manager.createChain(url, chainDefinition);
            }
        }

        return manager;
    }

1》 org.apache.shiro.web.filter.mgt.DefaultFilterChainManager#DefaultFilterChainManager() 构造如下:

    public DefaultFilterChainManager() {
        this.filters = new LinkedHashMap<String, Filter>();
        this.filterChains = new LinkedHashMap<String, NamedFilterList>();
        addDefaultFilters(false);
    }

    protected void addDefaultFilters(boolean init) {
        for (DefaultFilter defaultFilter : DefaultFilter.values()) {
            addFilter(defaultFilter.name(), defaultFilter.newInstance(), init, false);
        }
    }

org.apache.shiro.web.filter.mgt.DefaultFilter 枚举类型是shiro 内置的一些的默认过滤器, 我们也可以模仿其中的过滤器进行替换或者增加自己的filter

import org.apache.shiro.util.ClassUtils;
import org.apache.shiro.web.filter.authc.*;
import org.apache.shiro.web.filter.authz.*;
import org.apache.shiro.web.filter.session.NoSessionCreationFilter;

import javax.servlet.Filter;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * Enum representing all of the default Shiro Filter instances available to web applications.  Each filter instance is
 * typically accessible in configuration the {@link #name() name} of the enum constant.
 *
 * @since 1.0
 */
public enum DefaultFilter {

    anon(AnonymousFilter.class),
    authc(FormAuthenticationFilter.class),
    authcBasic(BasicHttpAuthenticationFilter.class),
    authcBearer(BearerHttpAuthenticationFilter.class),
    logout(LogoutFilter.class),
    noSessionCreation(NoSessionCreationFilter.class),
    perms(PermissionsAuthorizationFilter.class),
    port(PortFilter.class),
    rest(HttpMethodPermissionFilter.class),
    roles(RolesAuthorizationFilter.class),
    ssl(SslFilter.class),
    user(UserFilter.class);

    private final Class<? extends Filter> filterClass;

    private DefaultFilter(Class<? extends Filter> filterClass) {
        this.filterClass = filterClass;
    }

    public Filter newInstance() {
        return (Filter) ClassUtils.newInstance(this.filterClass);
    }

    public Class<? extends Filter> getFilterClass() {
        return this.filterClass;
    }

    public static Map<String, Filter> createInstanceMap(FilterConfig config) {
        Map<String, Filter> filters = new LinkedHashMap<String, Filter>(values().length);
        for (DefaultFilter defaultFilter : values()) {
            Filter filter = defaultFilter.newInstance();
            if (config != null) {
                try {
                    filter.init(config);
                } catch (ServletException e) {
                    String msg = "Unable to correctly init default filter instance of type " +
                            filter.getClass().getName();
                    throw new IllegalStateException(msg, e);
                }
            }
            filters.put(defaultFilter.name(), filter);
        }
        return filters;
    }
}

  这里面每个枚举处理一种,比如 anon 是匿名请求都可以访问; authc 是认证后可以看; perms 是有响应权限可以看;  roles 是有相应角色可以看;ssl 是只有https请求可以访问。

以AnonymousFilter 为例子查看:

源码如下:

public class AnonymousFilter extends PathMatchingFilter {

    /**
     * Always returns <code>true</code> allowing unchecked access to the underlying path or resource.
     *
     * @return <code>true</code> always, allowing unchecked access to the underlying path or resource.
     */
    @Override
    protected boolean onPreHandle(ServletRequest request, ServletResponse response, Object mappedValue) {
        // Always return true since we allow access to anyone
        return true;
    }

}

其继承图如下:(可以看出本质也是一个javax.servlet.Filter, 这种filter 没有添加到servlet 环境,那么是如何发挥作用的?下节研究。)

2》 getFilters() 从org.apache.shiro.spring.web.ShiroFilterFactoryBean#filters 属性中拿自己手动设置的过滤器。 如果是name 和上面默认的一样,会进行覆盖; 如果name 不一样会进行新增。最终新增或者覆盖的还是org.apache.shiro.web.filter.mgt.DefaultFilterChainManager#filters 内部的元素。

    将来如果需要新增自己的filter,可以设置到这个属性中; 如果需要替换已有的filter, 也可以设置到这个属性中,name 和原来的一致就回覆盖。

3》 getFilterChainDefinitionMap() 获取到自己设置的url 和 过滤器匹配规则,然后调用 org.apache.shiro.web.filter.mgt.DefaultFilterChainManager#createChain 解析每个url 对应的过滤器链条。 

org.apache.shiro.web.filter.mgt.DefaultFilterChainManager#createChain:

    public void createChain(String chainName, String chainDefinition) {
        if (!StringUtils.hasText(chainName)) {
            throw new NullPointerException("chainName cannot be null or empty.");
        }
        if (!StringUtils.hasText(chainDefinition)) {
            throw new NullPointerException("chainDefinition cannot be null or empty.");
        }

        if (log.isDebugEnabled()) {
            log.debug("Creating chain [" + chainName + "] from String definition [" + chainDefinition + "]");
        }

        //parse the value by tokenizing it to get the resulting filter-specific config entries
        //
        //e.g. for a value of
        //
        //     "authc, roles[admin,user], perms[file:edit]"
        //
        // the resulting token array would equal
        //
        //     { "authc", "roles[admin,user]", "perms[file:edit]" }
        //
        String[] filterTokens = splitChainDefinition(chainDefinition);

        //each token is specific to each filter.
        //strip the name and extract any filter-specific config between brackets [ ]
        for (String token : filterTokens) {
            String[] nameConfigPair = toNameConfigPair(token);

            //now we have the filter name, path and (possibly null) path-specific config.  Let's apply them:
            addToChain(chainName, nameConfigPair[0], nameConfigPair[1]);
        }
    }

    protected String[] splitChainDefinition(String chainDefinition) {
        return StringUtils.split(chainDefinition, StringUtils.DEFAULT_DELIMITER_CHAR, '[', ']', true, true);
    }

    protected String[] toNameConfigPair(String token) throws ConfigurationException {

        try {
            String[] pair = token.split("\[", 2);
            String name = StringUtils.clean(pair[0]);

            if (name == null) {
                throw new IllegalArgumentException("Filter name not found for filter chain definition token: " + token);
            }
            String config = null;

            if (pair.length == 2) {
                config = StringUtils.clean(pair[1]);
                //if there was an open bracket, it assumed there is a closing bracket, so strip it too:
                config = config.substring(0, config.length() - 1);
                config = StringUtils.clean(config);

                //backwards compatibility prior to implementing SHIRO-205:
                //prior to SHIRO-205 being implemented, it was common for end-users to quote the config inside brackets
                //if that config required commas.  We need to strip those quotes to get to the interior quoted definition
                //to ensure any existing quoted definitions still function for end users:
                if (config != null && config.startsWith(""") && config.endsWith(""")) {
                    String stripped = config.substring(1, config.length() - 1);
                    stripped = StringUtils.clean(stripped);

                    //if the stripped value does not have any internal quotes, we can assume that the entire config was
                    //quoted and we can use the stripped value.
                    if (stripped != null && stripped.indexOf('"') == -1) {
                        config = stripped;
                    }
                    //else:
                    //the remaining config does have internal quotes, so we need to assume that each comma delimited
                    //pair might be quoted, in which case we need the leading and trailing quotes that we stripped
                    //So we ignore the stripped value.
                }
            }
            
            return new String[]{name, config};

        } catch (Exception e) {
            String msg = "Unable to parse filter chain definition token: " + token;
            throw new ConfigurationException(msg, e);
        }
    }

    public void addToChain(String chainName, String filterName, String chainSpecificFilterConfig) {
        if (!StringUtils.hasText(chainName)) {
            throw new IllegalArgumentException("chainName cannot be null or empty.");
        }
        Filter filter = getFilter(filterName);
        if (filter == null) {
            throw new IllegalArgumentException("There is no filter with name '" + filterName +
                    "' to apply to chain [" + chainName + "] in the pool of available Filters.  Ensure a " +
                    "filter with that name/path has first been registered with the addFilter method(s).");
        }

        applyChainConfig(chainName, filter, chainSpecificFilterConfig);

        NamedFilterList chain = ensureChain(chainName);
        chain.add(filter);
    }

    protected void applyChainConfig(String chainName, Filter filter, String chainSpecificFilterConfig) {
        if (log.isDebugEnabled()) {
            log.debug("Attempting to apply path [" + chainName + "] to filter [" + filter + "] " +
                    "with config [" + chainSpecificFilterConfig + "]");
        }
        if (filter instanceof PathConfigProcessor) {
            ((PathConfigProcessor) filter).processPathConfig(chainName, chainSpecificFilterConfig);
        } else {
            if (StringUtils.hasText(chainSpecificFilterConfig)) {
                //they specified a filter configuration, but the Filter doesn't implement PathConfigProcessor
                //this is an erroneous config:
                String msg = "chainSpecificFilterConfig was specified, but the underlying " +
                        "Filter instance is not an 'instanceof' " +
                        PathConfigProcessor.class.getName() + ".  This is required if the filter is to accept " +
                        "chain-specific configuration.";
                throw new ConfigurationException(msg);
            }
        }
    }

    protected NamedFilterList ensureChain(String chainName) {
        NamedFilterList chain = getChain(chainName);
        if (chain == null) {
            chain = new SimpleNamedFilterList(chainName);
            this.filterChains.put(chainName, chain);
        }
        return chain;
    }

    private Map<String, NamedFilterList> filterChains;
View Code

  解析我们为URL配置的过滤器以及相应的参数是在这一步, 也可以看到其解析以及字符串分割规则。

  这里代码的核心思想就是根据为每个URL建立一个对应的 NamedFilterList, 并将其需要经过的filter维持到NamedFilterList这个属性内部; 然后将这个 NamedFilterList 添加到 org.apache.shiro.web.filter.mgt.DefaultFilterChainManager#filterChains 属性中。

  比如上面的代码解析到的 filterChains如下:

(3) 创建一个PathMatchingFilterChainResolver 对象, 并将上面(2) 解析到的FilterChainManager 对象作为属性维持到 PathMatchingFilterChainResolver 内部

(4) 创建一个SpringShiroFilter, 并且构造方法上面传了 WebSecurityManager 和 PathMatchingFilterChainResolver。接下来后期对请求做处理的也就是这两个重要的属性。

  前期的准备以及解析工作已经完成,接下来请求进来就是这个filter 发挥作用。

【当你用心写完每一篇博客之后,你会发现它比你用代码实现功能更有成就感!】
原文地址:https://www.cnblogs.com/qlqwjy/p/15455543.html