Spring boot 集成Spring Security过程中的出现的关于Session scope的异常排查及解决方案

Spring boot 集成Spring Security过程中的出现的关于Session scope的异常排查及解决方案

背景介绍

最近做的一个项目，其一需要用到Spring 的oauth认证功能， 其二需要对spring 的ContextRefreshedEvent 这个事件进行监听，实现一部分自定义注解的功能（具体功能不作赘述），本来以为毫不相关的两个功能，却出现了一些意料之外的异常。下面是一些具体的异常排查过程以及最终的解决方案，若有部分理解错误或描述错误，欢迎指正（自创文章，如需转载请说明出处）。

场景

1. 引入Spring Security Oauth2，通过 @EnableOAuthClient 注解激活所需oauth认证功能
2. 监听ContextRefreshedEvent事件，从ApplicationContext中获取所有的bean names并根据相应的bean name获取到bean，具体代码如下：

/*** @author Lanny Yao* @date 8/30/2018 9:58 AM*/
@Component
public class Listener implements ApplicationListener<ContextRefreshedEvent> {@Overridepublic void onApplicationEvent(ContextRefreshedEvent event) {ApplicationContext context = ApplicationContext();String[] beanNames = BeanNamesForType(Object.class);for (String beanName : beanNames){Object bean = Bean(beanName);...}}
}

启动程序，抛出异常

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'scopedTarget.oauth2ClientContext': Scope 'session' is not active for the current thread; consider defining a scoped proxy for this bean if you intend to refer to it from a singleton; nested exception is java.lang.IllegalStateException: No thread-bound request found: Are you referring to request attributes outside of an actual web request, or processing a request outside of the originally receiving thread? If you are actually operating within a web request and still receive this message, your code is probably running outside of DispatcherServlet/DispatcherPortlet: In this case, use RequestContextListener or RequestContextFilter to expose the current request.at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:362) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]at org.springframework.beans.factory.Bean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]at t.Bean(AbstractApplicationContext.java:1089) ~[spring-context-5.0.8.RELEASE.jar:5.0.8.RELEASE]at com.lanny.blog.demo.ApplicationEvent(Listener.java:21) ~[classes/:na]at com.lanny.blog.demo.ApplicationEvent(Listener.java:12) ~[classes/:na]at t.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) ~[spring-context-5.0.8.RELEASE.jar:5.0.8.RELEASE]at t.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) ~[spring-context-5.0.8.RELEASE.jar:5.0.8.RELEASE]at t.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) ~[spring-context-5.0.8.RELEASE.jar:5.0.8.RELEASE]at t.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:400) ~[spring-context-5.0.8.RELEASE.jar:5.0.8.RELEASE]at t.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:354) ~[spring-context-5.0.8.RELEASE.jar:5.0.8.RELEASE]at t.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:888) ~[spring-context-5.0.8.RELEASE.jar:5.0.8.RELEASE]at org.springframework.boot.t.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext.java:161) ~[spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]at t.fresh(AbstractApplicationContext.java:553) ~[spring-context-5.0.8.RELEASE.jar:5.0.8.RELEASE]at org.springframework.boot.fresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]at org.springframework.fresh(SpringApplication.java:762) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]at org.springframework.freshContext(SpringApplication.java:398) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]at org.springframework.boot.SpringApplication.run(SpringApplication.java:330) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]at org.springframework.boot.SpringApplication.run(SpringApplication.java:1258) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]at com.lanny.blog.demo.seesionexception.SeesionexceptionApplication.main(SeesionexceptionApplication.java:14) [classes/:na]
Caused by: java.lang.IllegalStateException: No thread-bound request found: Are you referring to request attributes outside of an actual web request, or processing a request outside of the originally receiving thread? If you are actually operating within a web request and still receive this message, your code is probably running outside of DispatcherServlet/DispatcherPortlet: In this case, use RequestContextListener or RequestContextFilter to expose the current request.at org.t.request.RequestContextHolder.currentRequestAttributes(RequestContextHolder.java:131) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]at org.t.(SessionScope.java:55) ~[spring-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:350) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]... 19 common frames omitted

排查过程

起初一看，完全不知所云啊， 不能创建bean的异常倒是经常看到，但是明明是在getBean（），怎么还影响到了oauth2ClientContext 这个bean的创建了呢？看下面spring 的源代码（位于AbstractBeanFactory 中的doGetBean（）方法中），发现在根据scope和beanName获取相应bean的时候会有一个create Bean的操作，所以也就印证了上面说的问题。

try {Object scopedInstance = (beanName, () -> {beforePrototypeCreation(beanName);try {return createBean(beanName, mbd, args);}finally {afterPrototypeCreation(beanName);}});bean = getObjectForBeanInstance(scopedInstance, name, beanName, mbd);}catch (IllegalStateException ex) {throw new BeanCreationException(beanName,"Scope '" + scopeName + "' is not active for the current thread; consider defining a scoped proxy for this bean if you intend to refer to it from a singleton", ex);}
}

既然是oauth相关的bean，罪魁祸首肯定是@EnableOAuth2Client注解了，果不其然，注释掉该注解之后程序可以正常启动，而且试了几种其他的监听方式，发现只要用到了ApplicationContext 和这个注解，就会报错。你俩到底谁的锅，我来找找。
先看看这个oauth2ClientContext bean是在哪里定义的，全局搜索一下，发现一个代码片段，哟嗬，确实是被标记为“session” scope的，那么问题来了，是不是拥有“session”这个scope的bean都会出现这个异常呢

@Bean
@Scope(value = "session", proxyMode = ScopedProxyMode.INTERFACES)
public OAuth2ClientContext oauth2ClientContext() {return new DefaultOAuth2ClientContext(accessTokenRequest);
}

try catch 一下：

Error bean -> [scopedTarget.oauth2ClientContext], caused by:Error creating bean with name 'scopedTarget.oauth2ClientContext': Scope 'session' is not active for the current thread; consider defining a scoped proxy for this bean if you intend to refer to it from a singleton; nested exception is java.lang.IllegalStateException: No thread-bound request found: Are you referring to request attributes outside of an actual web request, or processing a request outside of the originally receiving thread? If you are actually operating within a web request and still receive this message, your code is probably running outside of DispatcherServlet/DispatcherPortlet: In this case, use RequestContextListener or RequestContextFilter to expose the current request.
Error bean -> [scopedTarget.accessTokenRequest], caused by:Error creating bean with name 'scopedTarget.accessTokenRequest': Scope 'request' is not active for the current thread; consider defining a scoped proxy for this bean if you intend to refer to it from a singleton; nested exception is java.lang.IllegalStateException: No thread-bound request found: Are you referring to request attributes outside of an actual web request, or processing a request outside of the originally receiving thread? If you are actually operating within a web request and still receive this message, your code is probably running outside of DispatcherServlet/DispatcherPortlet: In this case, use RequestContextListener or RequestContextFilter to expose the current request.

发现还有另外一个bean accessTokenRequest也出现问题了，这么看来不只是session scope， request scope的bean也出了问题，如此一来弄清楚scope的意义就变成首要任务了：

spring中bean的scope属性，有如下5种类型：singleton 表示在spring容器中的单例，通过spring容器获得该bean时总是返回唯一的实例
prototype表示每次获得bean都会生成一个新的对象
request表示在一次http请求内有效（只适用于web应用）
session表示在一个用户会话内有效（只适用于web应用）
globalSession表示在全局会话内有效（只适用于web应用）
在多数情况，我们只会使用singleton和prototype两种scope，如果在spring配置文件内未指定scope属性，默认为singleton。（摘自.html）

可以清楚的看到session 和request 的scope只适用于web应用，生命周期取决于http请求和session过期时间，所以通过Spring 上下文也就是ApplicationContext获取bean时,当beanName对应的bean的scope是“session”或者“request”之类时，其实是不允许直接创建的.所以到这里，异常出现的根本原因已经找到，所以代码里面需要做的就是： 过滤scope !

很庆幸，ApplicationContext本身就提供了方法判断scope，但是只能判断“singleton” 和“prototype”类型的：

if (context.isPrototype(beanName) || context.isSingleton(beanName))

ok，过滤完成，运行一下，WTF！加个判断条件，又给我出新的异常，让不让人活了！！！

2018-08-30 13:54:04.396  INFO 18784 --- [           main] ConditionEvaluationReportLoggingListener : Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-08-30 13:54:04.437 ERROR 18784 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : ***************************
APPLICATION FAILED TO START
***************************Description:A component required a bean named 'autoConfigurationReport' that could not be found.Action:Consider defining a bean named 'autoConfigurationReport' in your configuration.

这个更懵逼，感觉更加的毫不相关，研究源码之下发现scope 是singleton的bean是不能去调isPrototype（）方法的，调用后会出现这个异常，直接导致JVM挂掉，比之前的异常更加暴力。关于这一点没有去深究，不知道是出于什么策略会有这样的设计，还是说是因为其他的一些原因。其实没有特殊需求的情况下，工程项目下的自定义的所有的bean都默认scope是singleton的，所以，只需要找出singleton的bean 就能满足需求了

解决方案

1. context.isSingleton(beanName) 直接通过这个方法做判断找出所有的singleton的bean，但是如上所述这个方法存在风险
2. 可以看到代码里是通过 String[] beanNames = BeanNamesForType(Object.class);获取到的所有的bean name，对于这个方法，其实有两个参数可以使用，这是解决这个问题的关键，把第二个参数设置成false，就可以只取scope为singleton的bean了，第三个参数根据实际情况设置，我这里直接设为true。

String[] beanNames = BeanNamesForType(Object.class,false,true);

* @param type the class or interface to match, or {@code null} for all bean names* @param includeNonSingletons whether to include prototype or scoped beans too* or just singletons (also applies to FactoryBeans)* @param allowEagerInit whether to initialize <i>lazy-init singletons</i> and* <i>objects created by FactoryBeans</i> (or by factory methods with a* "factory-bean" reference) for the type check. Note that FactoryBeans need to be* eagerly initialized to determine their type: So be aware that passing in "true"* for this flag will initialize FactoryBeans and "factory-bean" references.* @return the names of beans (or objects created by FactoryBeans) matching* the given object type (including subclasses), or an empty array if none* @see FactoryBean#getObjectType* @see BeanFactoryUtils#beanNamesForTypeIncludingAncestors(ListableBeanFactory, Class, boolean, boolean)*/String[] getBeanNamesForType(@Nullable Class<?> type, boolean includeNonSingletons, boolean allowEagerInit);

至此，问题得以解决。