• db_table--Spring Security3.1 最新配置实例


    2011-04-28

    这几天学习了一下Spring Security3.1,从官网下载了Spring Security3.1版本进行练习,经过多次尝试才摸清了其中的一些原理。本人不才,希望能帮助大家。还有,这次我第二次写博客啊,文体不是很行。希望能让观看者不产生疲惫的感觉,我已经心满意足了。
    一、数据库结构
         先来看一下数据库结构,采用的是基于角色-资源-用户的权限管理设计。(MySql数据库)
        为了节省篇章,只对比较重要的字段进行注释。
        1.用户表Users
        CREATE TABLE `users` (
           -- 账号是否有限 1. 是 0.否
           `enable` int(11) default NULL,
           `password` varchar(255) default NULL,
           `account` varchar(255) default NULL,
           `id` int(11) NOT NULL auto_increment,
           PRIMARY KEY  (`id`)
        )
     
       2.角色表Roles
       CREATE TABLE `roles` (
         `enable` int(11) default NULL,
         `name` varchar(255) default NULL,
         `id` int(11) NOT NULL auto_increment,
         PRIMARY KEY  (`id`)
       )
     
       3 用户_角色表users_roles
       CREATE TABLE `users_roles` (
         --用户表的外键
         `uid` int(11) default NULL,
         --角色表的外键
         `rid` int(11) default NULL,
         `urId` int(11) NOT NULL auto_increment,
         PRIMARY KEY  (`urId`),
         KEY `rid` (`rid`),
         KEY `uid` (`uid`),
        CONSTRAINT `users_roles_ibfk_1` FOREIGN KEY (`rid`) REFERENCES `roles` (`id`),
        CONSTRAINT `users_roles_ibfk_2` FOREIGN KEY (`uid`) REFERENCES `users` (`id`)
       )
     
       4.资源表resources
       CREATE TABLE `resources` (
         `memo` varchar(255) default NULL,
         -- 权限所对应的url地址
         `url` varchar(255) default NULL,
         --优先权
         `priority` int(11) default NULL,
         --类型
         `type` int(11) default NULL,
         --权限所对应的编码,例201代表发表文章
         `name` varchar(255) default NULL,
         `id` int(11) NOT NULL auto_increment,
         PRIMARY KEY  (`id`)
       ) 
     
       5.角色_资源表roles_resources
        CREATE TABLE `roles_resources` (
          `rsid` int(11) default NULL,
          `rid` int(11) default NULL,
          `rrId` int(11) NOT NULL auto_increment,
          PRIMARY KEY  (`rrId`),
          KEY `rid` (`rid`),
          KEY `roles_resources_ibfk_2` (`rsid`),
          CONSTRAINT `roles_resources_ibfk_2` FOREIGN KEY (`rsid`) REFERENCES `resources` (`id`),
          CONSTRAINT `roles_resources_ibfk_1` FOREIGN KEY (`rid`) REFERENCES `roles` (`id`)
          )
     
      二、系统配置
       所需要的jar包,请自行到官网下载,我用的是Spring Security3.1.0.RC1版的。把dist下的除了源码件包导入就行了。还有那些零零碎的   数据库驱动啊,log4j.jar等等,我相信在用Spring Security之前,大家已经会的了。
      1) web.xml
      
    [xhtml] view plaincopyprint?
    <!-- Spring -->  
       <context-param>  
         <param-name>contextConfigLocation</param-name>  
         <param-value>classpath:applicationContext.xml,classpath:applicationContext-security.xml</param-value>  
       </context-param>  
         
           
       <listener>  
         <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>  
       </listener>  
       <!-- 权限 -->  
       <filter>  
             <filter-name>springSecurityFilterChain</filter-name>  
             <filter-class>  
                 org.springframework.web.filter.DelegatingFilterProxy  
             </filter-class>  
        </filter>  
         <filter-mapping>  
             <filter-name>springSecurityFilterChain</filter-name>  
             <url-pattern>/*</url-pattern>  
         </filter-mapping>  
    <!-- Spring --> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml,classpath:applicationContext-security.xml</param-value> </context-param> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <!-- 权限 --> <filter> <filter-name>springSecurityFilterChain</filter-name> <filter-class> org.springframework.web.filter.DelegatingFilterProxy </filter-class> </filter> <filter-mapping> <filter-name>springSecurityFilterChain</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> 
     这里主要是配置了让容器启动的时候加载application-security.xml和Spring Security的权限过滤器代理,让其过滤所有的客服请求。
     2)application-security.xml
      
    [xhtml] view plaincopyprint?
    <?xml version="1.0" encoding="UTF-8"?>  
     <beans:beans xmlns="http://www.springframework.org/schema/security"  
         xmlns:beans="http://www.springframework.org/schema/beans"  
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
         xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd  
                             http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.1.xsd">  
                               
         <global-method-security pre-post-annotations="enabled" />   
         <!-- 该路径下的资源不用过滤 -->             
         <http pattern="/js/**" security="none"/>  
         <http use-expressions="true" auto-config="true">  
               
             <form-login />  
             <logout/>  
             <!-- 实现免登陆验证 -->  
             <remember-me />  
             <session-management invalid-session-url="/timeout.jsp">  
                 <concurrency-control max-sessions="10" error-if-maximum-exceeded="true" />  
             </session-management>  
             <custom-filter ref="myFilter" before="FILTER_SECURITY_INTERCEPTOR"/>  
         </http>  
         <!-- 配置过滤器 -->  
         <beans:bean id="myFilter" class="com.huaxin.security.MySecurityFilter">  
             <!-- 用户拥有的权限 -->  
             <beans:property name="authenticationManager" ref="myAuthenticationManager" />  
             <!-- 用户是否拥有所请求资源的权限 -->  
             <beans:property name="accessDecisionManager" ref="myAccessDecisionManager" />  
             <!-- 资源与权限对应关系 -->  
             <beans:property name="securityMetadataSource" ref="mySecurityMetadataSource" />  
         </beans:bean>  
         <!-- 实现了UserDetailsService的Bean -->  
         <authentication-manager alias="myAuthenticationManager">  
             <authentication-provider user-service-ref="myUserDetailServiceImpl" />  
         </authentication-manager>  
         <beans:bean id="myAccessDecisionManager" class="com.huaxin.security.MyAccessDecisionManager"></beans:bean>  
         <beans:bean id="mySecurityMetadataSource" class="com.huaxin.security.MySecurityMetadataSource">  
             <beans:constructor-arg name="resourcesDao" ref="resourcesDao"></beans:constructor-arg>  
         </beans:bean>  
         <beans:bean id="myUserDetailServiceImpl" class="com.huaxin.security.MyUserDetailServiceImpl">  
             <beans:property name="usersDao" ref="usersDao"></beans:property>  
         </beans:bean>  
     </beans:beans>  
    <?xml version="1.0" encoding="UTF-8"?> <beans:beans xmlns="http://www.springframework.org/schema/security" xmlns:beans="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.1.xsd"> <global-method-security pre-post-annotations="enabled" /> <!-- 该路径下的资源不用过滤 --> <http pattern="/js/**" security="none"/> <http use-expressions="true" auto-config="true"> <form-login /> <logout/> <!-- 实现免登陆验证 --> <remember-me /> <session-management invalid-session-url="/timeout.jsp"> <concurrency-control max-sessions="10" error-if-maximum-exceeded="true" /> </session-management> <custom-filter ref="myFilter" before="FILTER_SECURITY_INTERCEPTOR"/> </http> <!-- 配置过滤器 --> <beans:bean id="myFilter" class="com.huaxin.security.MySecurityFilter"> <!-- 用户拥有的权限 --> <beans:property name="authenticationManager" ref="myAuthenticationManager" /> <!-- 用户是否拥有所请求资源的权限 --> <beans:property name="accessDecisionManager" ref="myAccessDecisionManager" /> <!-- 资源与权限对应关系 --> <beans:property name="securityMetadataSource" ref="mySecurityMetadataSource" /> </beans:bean> <!-- 实现了UserDetailsService的Bean --> <authentication-manager alias="myAuthenticationManager"> <authentication-provider user-service-ref="myUserDetailServiceImpl" /> </authentication-manager> <beans:bean id="myAccessDecisionManager" class="com.huaxin.security.MyAccessDecisionManager"></beans:bean> <beans:bean id="mySecurityMetadataSource" class="com.huaxin.security.MySecurityMetadataSource"> <beans:constructor-arg name="resourcesDao" ref="resourcesDao"></beans:constructor-arg> </beans:bean> <beans:bean id="myUserDetailServiceImpl" class="com.huaxin.security.MyUserDetailServiceImpl"> <beans:property name="usersDao" ref="usersDao"></beans:property> </beans:bean> </beans:beans> 
     
    我们在第二个http标签下配置一个我们自定义的继承了org.springframework.security.access.intercept.AbstractSecurityInterceptor的Filter,并注入其
    必须的3个组件authenticationManager、accessDecisionManager和securityMetadataSource。其作用上面已经注释了。
     
    <custom-filter ref="myFilter" before="FILTER_SECURITY_INTERCEPTOR"/> 这里的FILTER_SECURITY_INTERCEPTOR是Spring Security默认的Filter,
    我们自定义的Filter必须在它之前,过滤客服请求。接下来看下我们最主要的myFilter吧。
     
    3)myFilter
      (1) MySecurityFilter.java 过滤用户请求
      
    [java] view plaincopyprint?
    public class MySecurityFilter extends AbstractSecurityInterceptor implements Filter {  
         //与applicationContext-security.xml里的myFilter的属性securityMetadataSource对应,   
         //其他的两个组件,已经在AbstractSecurityInterceptor定义   
         private FilterInvocationSecurityMetadataSource securityMetadataSource;  
       
         @Override  
         public SecurityMetadataSource obtainSecurityMetadataSource() {  
             return this.securityMetadataSource;  
         }  
       
         public void doFilter(ServletRequest request, ServletResponse response,  
                 FilterChain chain) throws IOException, ServletException {  
             FilterInvocation fi = new FilterInvocation(request, response, chain);  
             invoke(fi);  
         }  
           
         private void invoke(FilterInvocation fi) throws IOException, ServletException {  
             // object为FilterInvocation对象   
                       //super.beforeInvocation(fi);源码   
             //1.获取请求资源的权限   
             //执行Collection<ConfigAttribute> attributes = SecurityMetadataSource.getAttributes(object);   
             //2.是否拥有权限   
             //this.accessDecisionManager.decide(authenticated, object, attributes);   
             InterceptorStatusToken token = super.beforeInvocation(fi);  
             try {  
                 fi.getChain().doFilter(fi.getRequest(), fi.getResponse());  
             } finally {  
                 super.afterInvocation(token, null);  
             }  
         }  
       
         public FilterInvocationSecurityMetadataSource getSecurityMetadataSource() {  
             return securityMetadataSource;  
         }  
       
         public void setSecurityMetadataSource(FilterInvocationSecurityMetadataSource securityMetadataSource) {  
             this.securityMetadataSource = securityMetadataSource;  
         }  
           
         public void init(FilterConfig arg0) throws ServletException {  
             // TODO Auto-generated method stub   
         }  
           
         public void destroy() {  
             // TODO Auto-generated method stub   
               
         }  
       
         @Override  
         public Class<? extends Object> getSecureObjectClass() {  
             //下面的MyAccessDecisionManager的supports方面必须放回true,否则会提醒类型错误   
             return FilterInvocation.class;  
         }  
     }  
    public class MySecurityFilter extends AbstractSecurityInterceptor implements Filter { //与applicationContext-security.xml里的myFilter的属性securityMetadataSource对应, //其他的两个组件,已经在AbstractSecurityInterceptor定义 private FilterInvocationSecurityMetadataSource securityMetadataSource; @Override public SecurityMetadataSource obtainSecurityMetadataSource() { return this.securityMetadataSource; } public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { FilterInvocation fi = new FilterInvocation(request, response, chain); invoke(fi); } private void invoke(FilterInvocation fi) throws IOException, ServletException { // object为FilterInvocation对象 //super.beforeInvocation(fi);源码 //1.获取请求资源的权限 //执行Collection<ConfigAttribute> attributes = SecurityMetadataSource.getAttributes(object); //2.是否拥有权限 //this.accessDecisionManager.decide(authenticated, object, attributes); InterceptorStatusToken token = super.beforeInvocation(fi); try { fi.getChain().doFilter(fi.getRequest(), fi.getResponse()); } finally { super.afterInvocation(token, null); } } public FilterInvocationSecurityMetadataSource getSecurityMetadataSource() { return securityMetadataSource; } public void setSecurityMetadataSource(FilterInvocationSecurityMetadataSource securityMetadataSource) { this.securityMetadataSource = securityMetadataSource; } public void init(FilterConfig arg0) throws ServletException { // TODO Auto-generated method stub } public void destroy() { // TODO Auto-generated method stub } @Override public Class<? extends Object> getSecureObjectClass() { //下面的MyAccessDecisionManager的supports方面必须放回true,否则会提醒类型错误 return FilterInvocation.class; } } 
      核心的InterceptorStatusToken token = super.beforeInvocation(fi);会调用我们定义的accessDecisionManager:decide(Object object)和securityMetadataSource
      :getAttributes(Object object)方法。
     
     (2)MySecurityMetadataSource.java
      
    [java] view plaincopyprint?
    //1 加载资源与权限的对应关系   
     public class MySecurityMetadataSource implements FilterInvocationSecurityMetadataSource {  
         //由spring调用   
         public MySecurityMetadataSource(ResourcesDao resourcesDao) {  
             this.resourcesDao = resourcesDao;  
             loadResourceDefine();  
         }  
       
         private ResourcesDao resourcesDao;  
         private static Map<String, Collection<ConfigAttribute>> resourceMap = null;  
       
         public ResourcesDao getResourcesDao() {  
             return resourcesDao;  
         }  
       
         public void setResourcesDao(ResourcesDao resourcesDao) {  
             this.resourcesDao = resourcesDao;  
         }  
       
         public Collection<ConfigAttribute> getAllConfigAttributes() {  
             // TODO Auto-generated method stub   
             return null;  
         }  
       
         public boolean supports(Class<?> clazz) {  
             // TODO Auto-generated method stub   
             return true;  
         }  
         //加载所有资源与权限的关系   
         private void loadResourceDefine() {  
             if(resourceMap == null) {  
                 resourceMap = new HashMap<String, Collection<ConfigAttribute>>();  
                 List<Resources> resources = this.resourcesDao.findAll();  
                 for (Resources resource : resources) {  
                     Collection<ConfigAttribute> configAttributes = new ArrayList<ConfigAttribute>();  
                                     //以权限名封装为Spring的security Object   
                     ConfigAttribute configAttribute = new SecurityConfig(resource.getName());  
                     configAttributes.add(configAttribute);  
                     resourceMap.put(resource.getUrl(), configAttributes);  
                 }  
             }  
               
             Set<Entry<String, Collection<ConfigAttribute>>> resourceSet = resourceMap.entrySet();  
             Iterator<Entry<String, Collection<ConfigAttribute>>> iterator = resourceSet.iterator();  
               
         }  
         //返回所请求资源所需要的权限   
         public Collection<ConfigAttribute> getAttributes(Object object) throws IllegalArgumentException {  
               
             String requestUrl = ((FilterInvocation) object).getRequestUrl();  
             System.out.println("requestUrl is " + requestUrl);  
             if(resourceMap == null) {  
                 loadResourceDefine();  
             }  
             return resourceMap.get(requestUrl);  
         }  
       
     }  
    //1 加载资源与权限的对应关系 public class MySecurityMetadataSource implements FilterInvocationSecurityMetadataSource { //由spring调用 public MySecurityMetadataSource(ResourcesDao resourcesDao) { this.resourcesDao = resourcesDao; loadResourceDefine(); } private ResourcesDao resourcesDao; private static Map<String, Collection<ConfigAttribute>> resourceMap = null; public ResourcesDao getResourcesDao() { return resourcesDao; } public void setResourcesDao(ResourcesDao resourcesDao) { this.resourcesDao = resourcesDao; } public Collection<ConfigAttribute> getAllConfigAttributes() { // TODO Auto-generated method stub return null; } public boolean supports(Class<?> clazz) { // TODO Auto-generated method stub return true; } //加载所有资源与权限的关系 private void loadResourceDefine() { if(resourceMap == null) { resourceMap = new HashMap<String, Collection<ConfigAttribute>>(); List<Resources> resources = this.resourcesDao.findAll(); for (Resources resource : resources) { Collection<ConfigAttribute> configAttributes = new ArrayList<ConfigAttribute>(); //以权限名封装为Spring的security Object ConfigAttribute configAttribute = new SecurityConfig(resource.getName()); configAttributes.add(configAttribute); resourceMap.put(resource.getUrl(), configAttributes); } } Set<Entry<String, Collection<ConfigAttribute>>> resourceSet = resourceMap.entrySet(); Iterator<Entry<String, Collection<ConfigAttribute>>> iterator = resourceSet.iterator(); } //返回所请求资源所需要的权限 public Collection<ConfigAttribute> getAttributes(Object object) throws IllegalArgumentException { String requestUrl = ((FilterInvocation) object).getRequestUrl(); System.out.println("requestUrl is " + requestUrl); if(resourceMap == null) { loadResourceDefine(); } return resourceMap.get(requestUrl); } } 
     这里的resourcesDao,熟悉Dao设计模式和Spring 注入的朋友应该看得明白。
     
    (3)MyUserDetailServiceImpl.java
      
    [java] view plaincopyprint?
    public class MyUserDetailServiceImpl implements UserDetailsService {  
           
         private UsersDao usersDao;  
         public UsersDao getUsersDao() {  
             return usersDao;  
         }  
       
         public void setUsersDao(UsersDao usersDao) {  
             this.usersDao = usersDao;  
         }  
           
         public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {  
             System.out.println("username is " + username);  
             Users users = this.usersDao.findByName(username);  
             if(users == null) {  
                 throw new UsernameNotFoundException(username);  
             }  
             Collection<GrantedAuthority> grantedAuths = obtionGrantedAuthorities(users);  
               
             boolean enables = true;  
             boolean accountNonExpired = true;  
             boolean credentialsNonExpired = true;  
             boolean accountNonLocked = true;  
               
             User userdetail = new User(users.getAccount(), users.getPassword(), enables, accountNonExpired, credentialsNonExpired, accountNonLocked, grantedAuths);  
             return userdetail;  
         }  
           
         //取得用户的权限   
         private Set<GrantedAuthority> obtionGrantedAuthorities(Users user) {  
             Set<GrantedAuthority> authSet = new HashSet<GrantedAuthority>();  
             Set<Roles> roles = user.getRoles();  
               
             for(Roles role : roles) {  
                 Set<Resources> tempRes = role.getResources();  
                 for(Resources res : tempRes) {  
                     authSet.add(new GrantedAuthorityImpl(res.getName()));  
     s           }  
             }  
             return authSet;  
         }  
     }  
    public class MyUserDetailServiceImpl implements UserDetailsService { private UsersDao usersDao; public UsersDao getUsersDao() { return usersDao; } public void setUsersDao(UsersDao usersDao) { this.usersDao = usersDao; } public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException { System.out.println("username is " + username); Users users = this.usersDao.findByName(username); if(users == null) { throw new UsernameNotFoundException(username); } Collection<GrantedAuthority> grantedAuths = obtionGrantedAuthorities(users); boolean enables = true; boolean accountNonExpired = true; boolean credentialsNonExpired = true; boolean accountNonLocked = true; User userdetail = new User(users.getAccount(), users.getPassword(), enables, accountNonExpired, credentialsNonExpired, accountNonLocked, grantedAuths); return userdetail; } //取得用户的权限 private Set<GrantedAuthority> obtionGrantedAuthorities(Users user) { Set<GrantedAuthority> authSet = new HashSet<GrantedAuthority>(); Set<Roles> roles = user.getRoles(); for(Roles role : roles) { Set<Resources> tempRes = role.getResources(); for(Resources res : tempRes) { authSet.add(new GrantedAuthorityImpl(res.getName())); s } } return authSet; } } 
     
    (4) MyAccessDecisionManager.java
    [java] view plaincopyprint?
    public class MyAccessDecisionManager implements AccessDecisionManager {  
           
         public void decide(Authentication authentication, Object object, Collection<ConfigAttribute> configAttributes) throws AccessDeniedException, InsufficientAuthenticationException {  
             if(configAttributes == null) {  
                 return;  
             }  
             //所请求的资源拥有的权限(一个资源对多个权限)   
             Iterator<ConfigAttribute> iterator = configAttributes.iterator();  
             while(iterator.hasNext()) {  
                 ConfigAttribute configAttribute = iterator.next();  
                 //访问所请求资源所需要的权限   
                 String needPermission = configAttribute.getAttribute();  
                 System.out.println("needPermission is " + needPermission);  
                 //用户所拥有的权限authentication   
                 for(GrantedAuthority ga : authentication.getAuthorities()) {  
                     if(needPermission.equals(ga.getAuthority())) {  
                         return;  
                     }  
                 }  
             }  
             //没有权限   
             throw new AccessDeniedException(" 没有权限访问! ");  
         }  
       
         public boolean supports(ConfigAttribute attribute) {  
             // TODO Auto-generated method stub   
             return true;  
         }  
       
         public boolean supports(Class<?> clazz) {  
             // TODO Auto-generated method stub   
             return true;  
         }  
           
     }  
    public class MyAccessDecisionManager implements AccessDecisionManager { public void decide(Authentication authentication, Object object, Collection<ConfigAttribute> configAttributes) throws AccessDeniedException, InsufficientAuthenticationException { if(configAttributes == null) { return; } //所请求的资源拥有的权限(一个资源对多个权限) Iterator<ConfigAttribute> iterator = configAttributes.iterator(); while(iterator.hasNext()) { ConfigAttribute configAttribute = iterator.next(); //访问所请求资源所需要的权限 String needPermission = configAttribute.getAttribute(); System.out.println("needPermission is " + needPermission); //用户所拥有的权限authentication for(GrantedAuthority ga : authentication.getAuthorities()) { if(needPermission.equals(ga.getAuthority())) { return; } } } //没有权限 throw new AccessDeniedException(" 没有权限访问! "); } public boolean supports(ConfigAttribute attribute) { // TODO Auto-generated method stub return true; } public boolean supports(Class<?> clazz) { // TODO Auto-generated method stub return true; } } 
     
    三、流程
     1)容器启动(MySecurityMetadataSource:loadResourceDefine加载系统资源与权限列表)
     2)用户发出请求
     3)过滤器拦截(MySecurityFilter:doFilter)
     4)取得请求资源所需权限(MySecurityMetadataSource:getAttributes)
     5)匹配用户拥有权限和请求权限(MyAccessDecisionManager:decide),如果用户没有相应的权限,
         执行第6步,否则执行第7步。
     6)登录
     7)验证并授权(MyUserDetailServiceImpl:loadUserByUsername)
     8)重复4,5
     
    四、结束语
    好了,终于写完了,回头看了一下,感觉不是怎么行。等我弄明白Spring Security它的原理之后,再回头修改下注释吧。大家觉得不妥的地方,可以留言,我会回复大家的。

    我已经把源码上传到CSDN了。http://download.csdn.net/source/3283687
  • 相关阅读:
    bzoj 1086 [SCOI2005]王室联邦——思路
    bzoj 3809 Gty的二逼妹子序列——莫队+分块
    bzoj 3781 小B的询问——分块
    bzoj 3309 DZY Loves Math——反演+线性筛
    洛谷 1079 Vigenère 密码——模拟水题
    洛谷 1082 同余方程——exgcd(水题)
    bzoj2662 [BeiJing wc2012]冻结 ——分层图
    bzoj2242 [SDOI2011]计算器——BSGS
    bzoj1008 [HNOI2008]越狱——快速幂
    bzoj1607 [Usaco2008 Dec]Patting Heads 轻拍牛头——暴力
  • 原文地址:https://www.cnblogs.com/huapox/p/3516386.html
Copyright © 2020-2023  润新知