我是 spring boot 的新手，我想要在我的系统中构建一个 restful 服务，但是，在我将相关 Controller 添加到我的项目并启动服务器后，需要输入“用户”和我还没有设置的“密码”。我认为这是由默认安全配置引起的。所以我将 @EnableWebSecurity 添加为 the official doc在其余 Controller 上描述，我得到异常。
其余的 Controller 是:
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.hh.user.domain.User;
@EnableAutoConfiguration
@RestController
@RequestMapping("/user")
@EnableWebSecurity
@ConditionalOnMissingBean(WebSecurityConfiguration.class)
public class UserController {
@RequestMapping("/{id}")
public User view(@PathVariable("id") Long id) {
User user = new User();
user.setUSER_ID(id);
user.setUSER_LOGIN("yeah");
return user;
}
public static void main(String[] args) {
SpringApplication.run(UserController.class);
}
}
异常(exception)情况:
2014-06-23 02:26:56.610 INFO 7368 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2014-06-23 02:26:56.612 INFO 7368 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 3239 ms
2014-06-23 02:26:57.095 ERROR 7368 --- [cat-startStop-1] org.apache.catalina.core.ContainerBase : A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[]]
at java.util.concurrent.FutureTask.report(FutureTask.java:122)
at java.util.concurrent.FutureTask.get(FutureTask.java:188)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:799)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
... 6 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'springSecurityFilterChain' defined in class org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public javax.servlet.Filter org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration.springSecurityFilterChain() throws java.lang.Exception] threw exception; nested exception is java.lang.IllegalStateException: At least one non-null instance of WebSecurityConfigurer must be exposed as a @Bean when using @EnableWebSecurity. Hint try extending WebSecurityConfigurerAdapter
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:591)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1094)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:989)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.getOrderedBeansOfType(EmbeddedWebApplicationContext.java:367)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.getServletContextInitializerBeans(EmbeddedWebApplicationContext.java:268)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext$1.onStartup(EmbeddedWebApplicationContext.java:213)
at org.springframework.boot.context.embedded.tomcat.ServletContextInitializerLifecycleListener.lifecycleEvent(ServletContextInitializerLifecycleListener.java:54)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5355)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 6 common frames omitted
Caused by: org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public javax.servlet.Filter org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration.springSecurityFilterChain() throws java.lang.Exception] threw exception; nested exception is java.lang.IllegalStateException: At least one non-null instance of WebSecurityConfigurer must be exposed as a @Bean when using @EnableWebSecurity. Hint try extending WebSecurityConfigurerAdapter
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:188)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:580)
... 22 common frames omitted
Caused by: java.lang.IllegalStateException: At least one non-null instance of WebSecurityConfigurer must be exposed as a @Bean when using @EnableWebSecurity. Hint try extending WebSecurityConfigurerAdapter
at org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration.springSecurityFilterChain(WebSecurityConfiguration.java:90)
at org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration$$EnhancerBySpringCGLIB$$f97a43dc.CGLIB$springSecurityFilterChain$1(<generated>)
at org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration$$EnhancerBySpringCGLIB$$f97a43dc$$FastClassBySpringCGLIB$$5cecbbc6.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:312)
at org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration$$EnhancerBySpringCGLIB$$f97a43dc.springSecurityFilterChain(<generated>)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:166)
... 23 common frames omitted
2014-06-23 02:26:57.099 ERROR 7368 --- [ main] org.apache.catalina.core.ContainerBase : A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost]]
at java.util.concurrent.FutureTask.report(FutureTask.java:122)
at java.util.concurrent.FutureTask.get(FutureTask.java:188)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:731)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.startup.Tomcat.start(Tomcat.java:341)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.initialize(TomcatEmbeddedServletContainer.java:79)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.<init>(TomcatEmbeddedServletContainer.java:69)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getTomcatEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:284)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:146)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.createEmbeddedServletContainer(EmbeddedWebApplicationContext.java:159)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:132)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:476)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:120)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:683)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:313)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:944)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:933)
at com.hh.binary.controller.UserController.main(UserController.java:30)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1131)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:799)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 6 common frames omitted
2014-06-23 02:26:57.104 INFO 7368 --- [ main] .b.l.ClasspathLoggingApplicationListener : Application failed to start with classpath: [file:/C:/Users/shijunji/wsFucking/exam-binary/target/classes/, file:/C:/Users/shijunji/.m2/repository/org/springframework/boot/spring-boot-starter-web/1.1.1.RELEASE/spring-boot-starter-web-1.1.1.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/boot/spring-boot-starter/1.1.1.RELEASE/spring-boot-starter-1.1.1.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/boot/spring-boot/1.1.1.RELEASE/spring-boot-1.1.1.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/boot/spring-boot-autoconfigure/1.1.1.RELEASE/spring-boot-autoconfigure-1.1.1.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/boot/spring-boot-starter-logging/1.1.1.RELEASE/spring-boot-starter-logging-1.1.1.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/slf4j/jul-to-slf4j/1.7.7/jul-to-slf4j-1.7.7.jar, file:/C:/Users/shijunji/.m2/repository/org/slf4j/log4j-over-slf4j/1.7.7/log4j-over-slf4j-1.7.7.jar, file:/C:/Users/shijunji/.m2/repository/ch/qos/logback/logback-classic/1.1.2/logback-classic-1.1.2.jar, file:/C:/Users/shijunji/.m2/repository/ch/qos/logback/logback-core/1.1.2/logback-core-1.1.2.jar, file:/C:/Users/shijunji/.m2/repository/org/yaml/snakeyaml/1.13/snakeyaml-1.13.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/boot/spring-boot-starter-tomcat/1.1.1.RELEASE/spring-boot-starter-tomcat-1.1.1.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/apache/tomcat/embed/tomcat-embed-core/7.0.54/tomcat-embed-core-7.0.54.jar, file:/C:/Users/shijunji/.m2/repository/org/apache/tomcat/embed/tomcat-embed-el/7.0.54/tomcat-embed-el-7.0.54.jar, file:/C:/Users/shijunji/.m2/repository/org/apache/tomcat/embed/tomcat-embed-logging-juli/7.0.54/tomcat-embed-logging-juli-7.0.54.jar, file:/C:/Users/shijunji/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.3.3/jackson-databind-2.3.3.jar, file:/C:/Users/shijunji/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.3.3/jackson-annotations-2.3.3.jar, file:/C:/Users/shijunji/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.3.3/jackson-core-2.3.3.jar, file:/C:/Users/shijunji/.m2/repository/org/hibernate/hibernate-validator/5.0.3.Final/hibernate-validator-5.0.3.Final.jar, file:/C:/Users/shijunji/.m2/repository/javax/validation/validation-api/1.1.0.Final/validation-api-1.1.0.Final.jar, file:/C:/Users/shijunji/.m2/repository/org/jboss/logging/jboss-logging/3.1.1.GA/jboss-logging-3.1.1.GA.jar, file:/C:/Users/shijunji/.m2/repository/com/fasterxml/classmate/1.0.0/classmate-1.0.0.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/spring-core/4.0.2.RELEASE/spring-core-4.0.2.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/spring-webmvc/4.0.2.RELEASE/spring-webmvc-4.0.2.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/spring-beans/4.0.2.RELEASE/spring-beans-4.0.2.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/spring-expression/4.0.2.RELEASE/spring-expression-4.0.2.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/javax/servlet/javax.servlet-api/3.0.1/javax.servlet-api-3.0.1.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/security/spring-security-core/3.2.3.RELEASE/spring-security-core-3.2.3.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/aopalliance/aopalliance/1.0/aopalliance-1.0.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/spring-aop/4.0.2.RELEASE/spring-aop-4.0.2.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/security/spring-security-web/3.2.3.RELEASE/spring-security-web-3.2.3.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/security/spring-security-config/3.2.3.RELEASE/spring-security-config-3.2.3.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/spring-tx/4.0.2.RELEASE/spring-tx-4.0.2.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/spring-jdbc/4.0.2.RELEASE/spring-jdbc-4.0.2.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/com/mchange/c3p0/0.9.5-pre8/c3p0-0.9.5-pre8.jar, file:/C:/Users/shijunji/.m2/repository/com/mchange/mchange-commons-java/0.2.7/mchange-commons-java-0.2.7.jar, file:/C:/Users/shijunji/.m2/repository/mysql/mysql-connector-java/5.1.30/mysql-connector-java-5.1.30.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/spring-context/4.0.2.RELEASE/spring-context-4.0.2.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/spring-orm/4.0.2.RELEASE/spring-orm-4.0.2.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/joda-time/joda-time/2.3/joda-time-2.3.jar, file:/C:/Users/shijunji/.m2/repository/com/google/guava/guava/r09/guava-r09.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/spring-web/4.0.2.RELEASE/spring-web-4.0.2.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/jstl/jstl/1.2/jstl-1.2.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/data/spring-data-mongodb/1.5.0.RELEASE/spring-data-mongodb-1.5.0.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/springframework/data/spring-data-commons/1.8.0.RELEASE/spring-data-commons-1.8.0.RELEASE.jar, file:/C:/Users/shijunji/.m2/repository/org/mongodb/mongo-java-driver/2.12.1/mongo-java-driver-2.12.1.jar, file:/C:/Users/shijunji/.m2/repository/org/slf4j/slf4j-api/1.7.7/slf4j-api-1.7.7.jar, file:/C:/Users/shijunji/.m2/repository/org/slf4j/jcl-over-slf4j/1.7.7/jcl-over-slf4j-1.7.7.jar]
2014-06-23 02:26:57.106 ERROR 7368 --- [ main] o.s.boot.SpringApplication : Application startup failed
org.springframework.context.ApplicationContextException: Unable to start embedded container; nested exception is org.springframework.boot.context.embedded.EmbeddedServletContainerException: Unable to start embedded Tomcat
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:135)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:476)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:120)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:683)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:313)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:944)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:933)
at com.hh.binary.controller.UserController.main(UserController.java:30)
Caused by: org.springframework.boot.context.embedded.EmbeddedServletContainerException: Unable to start embedded Tomcat
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.initialize(TomcatEmbeddedServletContainer.java:106)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.<init>(TomcatEmbeddedServletContainer.java:69)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getTomcatEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:284)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:146)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.createEmbeddedServletContainer(EmbeddedWebApplicationContext.java:159)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:132)
... 7 common frames omitted
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardServer[-1]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.startup.Tomcat.start(Tomcat.java:341)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.initialize(TomcatEmbeddedServletContainer.java:79)
... 12 common frames omitted
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Tomcat]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:731)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 14 common frames omitted
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 16 common frames omitted
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1131)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 18 common frames omitted
谁能帮我解释为什么 springSecurityFilterChain 被触发，以及如何禁用它？作为内部系统，其他服务是否需要授权？
提前致谢，如有任何建议，我们将不胜感激。
最佳答案
第一步:
添加类扩展 WebSecurityConfigurerAdapter:
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.method.configuration.EnableGlobalMethodSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(prePostEnabled = true)
public class BinarySecurityConfig extends WebSecurityConfigurerAdapter {
}
第 2 步: 在 src/main/resources 下添加文件 application.properties，内容如下
security.basic.enabled=false
我想知道是否有简单的方法，比如只做一个注释。
关于java - 未能关闭 Spring Boot 安全配置，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/24354550/