登录
当前位置： 首页 > 面试题库 >

在SecurityContext中找不到身份验证对象-Spring 3.2.2

太叔坚
2023-03-14
问题内容：

我试图从ApplicationListener<AuthenticationSuccessEvent>成功登录后实现接口的类（Spring 3.2.2和Spring Security 3.2.0 M1）中调用受保护的方法。这是我以前的问题。

该应用程序在以下环境下运行。

  • Spring 3.2.2
  • Spring Security 3.2.0
  • JPA 2.0
  • JSF 2.1.9
  • MySQL 5.6.11
  • JDK-7u11
  • NetBeans 7.2.1

我已经将以下与Spring安全性相关的库添加到类路径中。

  • spring-security-core-3.2.0.M1.jar
  • spring-security-config-3.2.0.M1.jar
  • spring-security-web-3.2.0.M1.jar

实现的类ApplicationListener<AuthenticationSuccessEvent>如下。

package loginsuccesshandler;

import admin.dao.service.StateService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationListener;
import org.springframework.security.authentication.event.AuthenticationSuccessEvent;
import org.springframework.stereotype.Service;

@Service
public final class AuthSuccessHandler implements ApplicationListener<AuthenticationSuccessEvent>
{
    @Autowired
    private StateService stateService;

    @Override
    public void onApplicationEvent(AuthenticationSuccessEvent event) 
    {
        System.out.println(event.getAuthentication());
        System.out.println("rowCount = "+stateService.rowCount());
    }
}

这可以防止用户使用以下消息使用正确的凭据登录（这只是一个示例。完全不需要对成功认证时的状态数进行计数）。

在SecurityContext中找不到身份验证对象

事件引发。方法中的第一条语句onApplicationEvent()显示以下内容。

org.springframework.security.authentication.UsernamePasswordAuthenticationToken@45264a59: Principal: org.springframework.security.core.userdetails.User@586034f:Username: admin; 
Password: [PROTECTED]; 
Enabled: true; 
AccountNonExpired: true; 
credentialsNonExpired: true; 
AccountNonLocked: true; 
Granted Authorities: ROLE_ADMIN; 
Credentials: [PROTECTED]; 
Authenticated: true; 
Details: org.springframework.security.web.authentication.WebAuthenticationDetails@380f4: RemoteIpAddress: 127.0.0.1; 
SessionId: 88777A678DC5BB0272F84CA4BC61FAF2;
Granted Authorities: ROLE_ADMIN

因此，似乎用户已通过身份验证，并且身份验证对象可用。

我的springSecurity.xml文件如下所示。

<?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-3.2.xsd
           http://www.springframework.org/schema/security
           http://www.springframework.org/schema/security/spring-security-3.1.xsd">

    <http pattern="/utility/Login.jsf*" security="none"/>
    <debug/>
    <http auto-config='true' use-expressions="true" disable-url-rewriting="true">
        <session-management session-fixation-protection="newSession">
            <concurrency-control max-sessions="1" error-if-maximum-exceeded="true" />
        </session-management>

        <intercept-url pattern="/admin_side/**" access="hasRole('ROLE_ADMIN')" requires-channel="any"/>
        <intercept-url pattern="/utility/Login.jsf" access="permitAll" requires-channel="any"/>
        <http-basic />
        <anonymous />

        <form-login login-processing-url="/j_spring_security_check" login-page="/utility/Login.jsf" authentication-success-handler-ref="loginSuccessHandler" authentication-failure-handler-ref="authenticationFailureHandler"/>
        <logout logout-success-url="/utility/Login.jsf" invalidate-session="true" delete-cookies="JSESSIONID"/>
    </http>

    <authentication-manager>
       <authentication-provider>
            <jdbc-user-service data-source-ref="dataSource"
               users-by-username-query="select email_id, password, enabled from user_table where lower(email_id)=lower(?)"
               authorities-by-username-query="select ut.email_id, ur.authority from user_table ut, user_roles ur where ut.user_id=ur.user_id and lower(ut.email_id)=lower(?)"/>
       </authentication-provider>
    </authentication-manager>

    <beans:bean id="loginSuccessHandler" class="loginsuccesshandler.LoginSuccessHandler"/>
    <beans:bean id="authenticationFailureHandler" class="loginsuccesshandler.AuthenticationFailureHandler" />        

    <global-method-security secured-annotations="enabled" pre-post-annotations="enabled" proxy-target-class="false">
        <protect-pointcut expression="execution(* admin.dao.*.*(..))" access="ROLE_ADMIN"/>
    </global-method-security>
</beans:beans>

当从spring-security.xml文件中省略以下XML行时，Spring安全性工作正常。

<global-method-security secured-annotations="enabled" proxy-target-class="false">
     <protect-pointcut expression="execution(* admin.dao.*.*(..))" access="ROLE_ADMIN"/>
</global-method-security>

可以从实现ApplicationListener<AuthenticationSuccessEvent>接口的类中调用受保护的方法（应用方法安全性）吗？如果是，那么我的情况缺少什么？到目前为止，我已经点击了成千上万的链接，但找不到任何线索。

该application-context.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:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:jee="http://www.springframework.org/schema/jee"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
       http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee.xsd
       http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
       http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">

    <context:component-scan base-package="admin.mangedbean loginsuccesshandler" use-default-filters="false">
        <context:include-filter expression="org.springframework.stereotype.Controller" type="annotation"/>
        <context:include-filter expression="org.springframework.web.bind.annotation.ControllerAdvice" type="annotation"/>  
    </context:component-scan>

    <mvc:annotation-driven/>
    <context:annotation-config/>

    <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/>            

    <bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="entityManagerFactory" >
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.enable_lazy_load_no_trans">true</prop>
            </props>
        </property>

        <property name="jpaPropertyMap">
            <map>
              <entry key="eclipselink.weaving" value="false"/>
            </map>
        </property>

        <property name="loadTimeWeaver">
            <bean class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver"/>
        </property>
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>

    <tx:annotation-driven transaction-manager="transactionManager"/>

    <bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
        <property name="jndiName" value="java:comp/env/jdbc/social_networking"/>
    </bean>

    <!--The bean shown in the beginning is configured here-->
    <bean id="authSuccessHandler" class="loginsuccesshandler.AuthSuccessHandler"/> 

    <bean id="testService" class="admin.dao.TestDAO"/>
    <bean id="stateService" class="admin.dao.StateDAO"/>
    <bean id="sharableService" class="admin.dao.SharableDAO"/>
</beans>

该web.xml文件。

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" 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_3_0.xsd">        

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            /WEB-INF/applicationContext.xml
            /WEB-INF/spring-security.xml
        </param-value>
    </context-param>

    <context-param>
        <param-name>javax.faces.PROJECT_STAGE</param-name>
        <!--<param-value>Development</param-value>-->
        <param-value>Production</param-value>
    </context-param>

    <context-param>
        <param-name>log4jConfigLocation</param-name>
        <param-value>/WEB-INF/log4j.properties</param-value>
    </context-param>

    <context-param>
        <param-name>log4jExposeWebAppRoot</param-name>
        <param-value>false</param-value>
    </context-param>

    <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>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
    </filter-mapping>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <listener>
        <listener-class>org.springframework.web.context.request.RequestContextListener</listener-class>
    </listener>        

    <listener>
        <listener-class>org.springframework.security.web.session.HttpSessionEventPublisher</listener-class>
    </listener>

    <listener>
        <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
    </listener>

    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.jsf</url-pattern>
    </servlet-mapping>

    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.xhtml</url-pattern>
    </servlet-mapping>

    <security-constraint>
        <display-name>Restrict direct access to XHTML files</display-name>
        <web-resource-collection>
            <web-resource-name>XHTML files</web-resource-name>
            <url-pattern>*.xhtml</url-pattern>
        </web-resource-collection>
        <auth-constraint />
    </security-constraint> 

    <session-config>
        <session-timeout>
            120
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>/utility/Login.jsf</welcome-file>
    </welcome-file-list>

    <resource-ref>
        <res-ref-name>jdbc/social_networking</res-ref-name>
        <res-type>javax.sql.DataSource</res-type>
        <res-auth>Container</res-auth>
    </resource-ref>
</web-app>

当尝试登录但最终失败时，可以在下面看到调试信息。

DEBUG [http-apr-8080-exec-55] (AntPathRequestMatcher.java:116) - Checking match of request : '/j_spring_security_check'; against '/utility/login.jsf*'
DEBUG [http-apr-8080-exec-55] (AntPathRequestMatcher.java:116) - Checking match of request : '/j_spring_security_check'; against '/utility/login.jsf*'
DEBUG [http-apr-8080-exec-55] (FilterChainProxy.java:337) - /j_spring_security_check at position 1 of 13 in additional filter chain; firing Filter: 'ChannelProcessingFilter'
DEBUG [http-apr-8080-exec-55] (AntPathRequestMatcher.java:116) - Checking match of request : '/j_spring_security_check'; against '/admin_side/**'
DEBUG [http-apr-8080-exec-55] (AntPathRequestMatcher.java:116) - Checking match of request : '/j_spring_security_check'; against '/utility/login.jsf'
DEBUG [http-apr-8080-exec-55] (FilterChainProxy.java:337) - /j_spring_security_check at position 2 of 13 in additional filter chain; firing Filter: 'SecurityContextPersistenceFilter'
DEBUG [http-apr-8080-exec-55] (HttpSessionSecurityContextRepository.java:139) - HttpSession returned null object for SPRING_SECURITY_CONTEXT
DEBUG [http-apr-8080-exec-55] (HttpSessionSecurityContextRepository.java:85) - No SecurityContext was available from the HttpSession: org.apache.catalina.session.StandardSessionFacade@1103da5. A new one will be created.
DEBUG [http-apr-8080-exec-55] (FilterChainProxy.java:337) - /j_spring_security_check at position 3 of 13 in additional filter chain; firing Filter: 'ConcurrentSessionFilter'
DEBUG [http-apr-8080-exec-55] (FilterChainProxy.java:337) - /j_spring_security_check at position 4 of 13 in additional filter chain; firing Filter: 'WebAsyncManagerIntegrationFilter'
DEBUG [http-apr-8080-exec-55] (FilterChainProxy.java:337) - /j_spring_security_check at position 5 of 13 in additional filter chain; firing Filter: 'LogoutFilter'
DEBUG [http-apr-8080-exec-55] (FilterChainProxy.java:337) - /j_spring_security_check at position 6 of 13 in additional filter chain; firing Filter: 'UsernamePasswordAuthenticationFilter'
DEBUG [http-apr-8080-exec-55] (AbstractAuthenticationProcessingFilter.java:189) - Request is to process authentication
DEBUG [http-apr-8080-exec-55] (ProviderManager.java:152) - Authentication attempt using org.springframework.security.authentication.dao.DaoAuthenticationProvider
DEBUG [http-apr-8080-exec-55] (JdbcTemplate.java:637) - Executing prepared SQL query
DEBUG [http-apr-8080-exec-55] (JdbcTemplate.java:572) - Executing prepared SQL statement [select email_id, password, enabled from user_table where lower(email_id)=lower(?)]
DEBUG [http-apr-8080-exec-55] (DataSourceUtils.java:110) - Fetching JDBC Connection from DataSource
DEBUG [http-apr-8080-exec-55] (DataSourceUtils.java:327) - Returning JDBC Connection to DataSource
DEBUG [http-apr-8080-exec-55] (JdbcTemplate.java:637) - Executing prepared SQL query
DEBUG [http-apr-8080-exec-55] (JdbcTemplate.java:572) - Executing prepared SQL statement [select ut.email_id, ur.authority from user_table ut, user_roles ur where ut.user_id=ur.user_id and lower(ut.email_id)=lower(?)]
DEBUG [http-apr-8080-exec-55] (DataSourceUtils.java:110) - Fetching JDBC Connection from DataSource
DEBUG [http-apr-8080-exec-55] (DataSourceUtils.java:327) - Returning JDBC Connection to DataSource
DEBUG [http-apr-8080-exec-55] (AbstractBeanFactory.java:246) - Returning cached instance of singleton bean 'authSuccessHandler'
DEBUG [http-apr-8080-exec-55] (AbstractBeanFactory.java:246) - Returning cached instance of singleton bean 'org.springframework.security.core.session.SessionRegistryImpl#0'
DEBUG [http-apr-8080-exec-55] (AbstractFallbackTransactionAttributeSource.java:106) - Adding transactional method 'rowCount' with attribute: PROPAGATION_REQUIRED,ISOLATION_DEFAULT,readOnly; ''
DEBUG [http-apr-8080-exec-55] (DelegatingMethodSecurityMetadataSource.java:65) - Caching method [CacheKey[admin.dao.StateDAO; public abstract java.lang.Long admin.dao.service.StateService.rowCount()]] with attributes [ROLE_ADMIN]
DEBUG [http-apr-8080-exec-55] (AbstractBeanFactory.java:246) - Returning cached instance of singleton bean 'transactionManager'
DEBUG [http-apr-8080-exec-55] (AbstractPlatformTransactionManager.java:366) - Creating new transaction with name [admin.dao.StateDAO.rowCount]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT,readOnly; ''
DEBUG [http-apr-8080-exec-55] (JpaTransactionManager.java:369) - Opened new EntityManager [org.hibernate.ejb.EntityManagerImpl@84ff11] for JPA transaction
DEBUG [http-apr-8080-exec-55] (JpaTransactionManager.java:408) - Not exposing JPA transaction [org.hibernate.ejb.EntityManagerImpl@84ff11] as JDBC transaction because JpaDialect [org.springframework.orm.jpa.DefaultJpaDialect@d9dbb8] does not support JDBC Connection retrieval
DEBUG [http-apr-8080-exec-55] (AbstractSecurityInterceptor.java:194) - Secure object: ReflectiveMethodInvocation: public abstract java.lang.Long admin.dao.service.StateService.rowCount(); target is of class [admin.dao.StateDAO]; Attributes: [ROLE_ADMIN]
DEBUG [http-apr-8080-exec-55] (AbstractBeanFactory.java:246) - Returning cached instance of singleton bean 'authSuccessHandler'
DEBUG [http-apr-8080-exec-55] (AbstractBeanFactory.java:246) - Returning cached instance of singleton bean 'org.springframework.security.core.session.SessionRegistryImpl#0'
DEBUG [http-apr-8080-exec-55] (AbstractPlatformTransactionManager.java:844) - Initiating transaction rollback
DEBUG [http-apr-8080-exec-55] (JpaTransactionManager.java:534) - Rolling back JPA transaction on EntityManager [org.hibernate.ejb.EntityManagerImpl@84ff11]
DEBUG [http-apr-8080-exec-55] (JpaTransactionManager.java:594) - Closing JPA EntityManager [org.hibernate.ejb.EntityManagerImpl@84ff11] after transaction
DEBUG [http-apr-8080-exec-55] (EntityManagerFactoryUtils.java:338) - Closing JPA EntityManager
DEBUG [http-apr-8080-exec-55] (AbstractAuthenticationProcessingFilter.java:346) - Authentication request failed: org.springframework.security.authentication.AuthenticationCredentialsNotFoundException: An Authentication object was not found in the SecurityContext
DEBUG [http-apr-8080-exec-55] (AbstractAuthenticationProcessingFilter.java:347) - Updated SecurityContextHolder to contain null Authentication
DEBUG [http-apr-8080-exec-55] (AbstractAuthenticationProcessingFilter.java:348) - Delegating to authentication failure handler loginsuccesshandler.AuthenticationFailureHandler@14883a3
DEBUG [http-apr-8080-exec-55] (DefaultRedirectStrategy.java:36) - Redirecting to '/SocialNetworking/utility/Login.jsf'
DEBUG [http-apr-8080-exec-55] (HttpSessionSecurityContextRepository.java:269) - SecurityContext is empty or contents are anonymous - context will not be stored in HttpSession.
DEBUG [http-apr-8080-exec-55] (SecurityContextPersistenceFilter.java:97) - SecurityContextHolder now cleared, as request processing completed
DEBUG [http-apr-8080-exec-49] (AntPathRequestMatcher.java:116) - Checking match of request : '/utility/login.jsf'; against '/utility/login.jsf*'
DEBUG [http-apr-8080-exec-49] (AntPathRequestMatcher.java:116) - Checking match of request : '/utility/login.jsf'; against '/utility/login.jsf*'
DEBUG [http-apr-8080-exec-49] (FilterChainProxy.java:180) - /utility/Login.jsf has an empty filter list

最后一件事情：

当我放弃该bean并从application-context.xml文件中注销时，登录成功，但是可以在服务器控制台上看到以下信息。

DEBUG [http-apr-8080-exec-165] (HttpSessionSecurityContextRepository.java:139) - HttpSession returned null object for SPRING_SECURITY_CONTEXT
DEBUG [http-apr-8080-exec-165] (HttpSessionSecurityContextRepository.java:85) - No SecurityContext was available from the HttpSession: org.apache.catalina.session.StandardSessionFacade@b910c1. A new one will be created.

问题答案：

安全性的授权检查部分从中获取已认证的对象SecurityContext，当请求通过spring安全性过滤器时将进行设置。我在这里的假设是，登录后不久就没有设置它。你可能可以使用下面提供的hack来设置值。

try {
    SecurityContext ctx = SecurityContextHolder.createEmptyContext();
    SecurityContextHolder.setContext(ctx);
    ctx.setAuthentication(event.getAuthentication());

    //Do what ever you want to do

} finally {
    SecurityContextHolder.clearContext();
}


 类似资料：
  • 在oauth2的SecurityContext中找不到身份验证对象

    我有一个使用spring security oauth2进行安全连接的项目。下面是我的spring配置文件。 Spring-安全.xml ： 当我使用以下请求请求oauth访问令牌时，我将获得如下访问和刷新令牌。 请求是 回应是: 然后，当我使用下面的请求请求受保护的资源时，我收到“在SecurityContext中找不到身份验证对象”作为错误。 请求是 ： 我使用“2.0.7.RELEASE”作

  • 在SecurityContext-Spring 5中未找到身份验证对象

    我是Spring Boot和Spring Security的新手，继承了一个使用它们的webapp项目。我们将把webapp迁移到新的部署环境中。我们要改变的事情之一是认证机制，以便它能在新环境中运行。同时，我想使用一些现有的PostMan测试来测试RESTendpoint，绕过安全性。基本上，我想暂时禁用安全。 我有一个提供全局方法级安全性的类： 我有多个控制器类,例如,一个类 如果我尝试运行邮

  • “在SecurityContext中找不到身份验证对象”-在Spring Boot中的UserDetails服务设置

    在Spring Boot应用程序中，我有一个内存中的Spring Security设置。它可以按照期望工作。 现在，我用以下代码将其转换为基于数据库的方法。 存储库： UserDetailsService： 以及对WebSecurity配置适配器配置的修改： 当我发送与内存版本相同的用户名和密码作为基本身份验证的请求时，我会得到401错误： 在阅读了一些相关文档和示例代码后，我看不出错误的原因。错

  • 在SecurityContext中找不到Spring Oauth2:Authentication对象

    我有一个实现Spring Security和Spring OAuth2安全的项目。当我请求访问令牌时，它工作得很好，但当我使用访问令牌请求资源时，我得到了“在SecurityContext中没有找到身份验证对象”。 我的项目的SecurityContext是： 我使用http://localhost:8060/oauth/token请求令牌？grant_type=password&client_i

  • Spring SecurityContext在错误页面上返回空身份验证

    问题内容： 我正在尝试为403（访问被拒绝）和500（内部服务器错误）之类的错误编写一个自定义错误页面。它们将从Velocity模板呈现，并使用用户的语言环境翻译所有消息。身份验证和区域设置解析在应用程序中运行良好。 我将web.xml中的位置设置为所需的页面，并在webmvc-context.xml中通过添加了Requet-to-view控制器。 我遇到的问题是 SecurityContextH

  • thymeleaf中的身份验证对象为空或空

    我用的是Spring boot Spring Security和Thymeleaf。目前，身份验证和授权工作良好时访问页面，但我不能使thymeleaf授权工作。流程非常简单：我尝试访问admin.html页面，对于该页面，我需要一个“admin”角色。Spring Security正确地截取了请求，首先将我转发到登录页面，当以管理员身份登录时，它允许我继续。 现在我想根据角色“隐藏”管理页面上的

相关阅读

Elasticsearch中的身份验证Webdriver-HTTP身份验证对话框php面向对象的用户登录身份验证Java / Mongodb身份验证Devise API身份验证

相关文章

PHP 表单验证jQuery 密码验证JavaScript表单验证Struts2 验证框架真找不到实习了🤡

相关问答

Laravel 5.5多重身份验证在身份验证时不重定向Spring Security中的Oauth2手动身份验证不会在整个会话中保持SecurityContextSpring Security OAuth2-存储的身份验证对象NoneType对象在Django中没有属性require_signatureSAML 2身份验证NSURLSession身份验证

相关工具

易优安身份认证ASP.NET语音验证码微擎表单验证Jquery表单验证插件SPT 对象数据库

相关文档

你不懂JS: this 与对象原型Python 面向对象Microsoft Office 对象参考XmlHttp 对象参考手册系统学习 PHP 与面向对象
快捷导航： 新手教程 算法原理 架构设计 Java进阶 数据库进阶 大厂专栏 面试经验 编程笔记 编程问答 所有专题 文档资料 工具软件 电子书籍 小牛导航
在线工具： 房贷计算器 个税计算器 Linux命令查询 Json格式化 正则表达式 颜色转换 AES加解密 SHA1加密 MD5加密 毒鸡汤 字数统计 随机密码生成 进制转换 Base64编解码 励志句子
Copyright © 2019-2024 小牛知识库@xnip.cn. All Rights Reserved.