Spring MVC：如何在生成的线程中使用请求范围的bean？

Question

package com.example.config

@Configuration
@ComponentScan(basePackages = { "com.example.scopetest" })
public class ScopeConfig {

    private Integer counter = new Integer(0);

    @Bean
    @Scope(value = "request", proxyMode = ScopedProxyMode.TARGET_CLASS)
    public Number counter() {
        counter = new Integer(counter.intValue() + 1);
        return counter;
    }


    /* Adding a org.springframework.social.facebook.api.Facebook request-scoped bean as a real-world example why all this matters
    @Bean
    @Scope(value = "request", proxyMode = ScopedProxyMode.INTERFACES)
    public Facebook facebook() {
    Connection<Facebook> facebook = connectionRepository()
            .findPrimaryConnection(Facebook.class);
    return facebook != null ? facebook.getApi() : new FacebookTemplate();
    }
    */

    ...................

}

package com.example.scopetest;

import javax.inject.Inject;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.springframework.social.facebook.api.Facebook;
import org.springframework.social.facebook.api.FacebookProfile;
import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class ScopeTestController {

    //@Inject
    //private Facebook facebook;

    @Inject
    private Number counter;

    private static final Logger logger = LoggerFactory
            .getLogger(ScopeTestController.class);

    @RequestMapping(value = "/scopetestnormal") 
    public void scopetestnormal() {
        logger.debug("About to interact with a request-scoped bean from HTTP request thread");
        logger.debug("counter is: {}", counter);

        /* 
         * The following also works
         * FacebookProfile profile = facebook.userOperations().getUserProfile();
         * logger.debug("Facebook user ID is: {}", profile.getId());    
         */
    }



    @RequestMapping(value = "/scopetestthread")
    public void scopetestthread() {
        logger.debug("About to spawn a new thread");
        new Thread(new RequestScopedBeanAccessingThread()).start();
        logger.debug("Spawned a new thread");
    }


    private class RequestScopedBeanAccessingThread implements Runnable {

        @Override
        public void run() {
            logger.debug("About to interact with a request-scoped bean from another thread. Doomed to fail.");          
            logger.debug("counter is: {}", counter);

            /*
             * The following is also doomed to fail
             * FacebookProfile profile = facebook.userOperations().getUserProfile();
             * logger.debug("Facebook user ID is: {}", profile.getId());        
             */
        }

    }

}

基于CGLIB的请求范围bean的堆栈跟踪(proxymode=scopedproxymode.target_class)

SLF4J: Failed toString() invocation on an object of type [$java.lang.Number$$EnhancerByCGLIB$$45ffcde7]
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'scopedTarget.counter': 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.
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:342)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.aop.target.SimpleBeanTargetSource.getTarget(SimpleBeanTargetSource.java:33)
    at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.getTarget(Cglib2AopProxy.java:654)
    at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:605)
    at $java.lang.Number$$EnhancerByCGLIB$$45ffcde7.toString(<generated>)
    at org.slf4j.helpers.MessageFormatter.safeObjectAppend(MessageFormatter.java:304)
    at org.slf4j.helpers.MessageFormatter.deeplyAppendParameter(MessageFormatter.java:276)
    at org.slf4j.helpers.MessageFormatter.arrayFormat(MessageFormatter.java:230)
    at ch.qos.logback.classic.spi.LoggingEvent.<init>(LoggingEvent.java:114)
    at ch.qos.logback.classic.Logger.buildLoggingEventAndAppend(Logger.java:447)18:09:48.276 container [Thread-16] DEBUG c.g.s.c.c.god.ScopeTestController - counter is: [FAILED toString()]

    at ch.qos.logback.classic.Logger.filterAndLog_1(Logger.java:421)
    at ch.qos.logback.classic.Logger.debug(Logger.java:514)
    at com.example.scopetest.ScopeTestController$RequestScopedBeanAccessingThread.run(ScopeTestController.java:58)
    at java.lang.Thread.run(Thread.java:722)
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.springframework.web.context.request.RequestContextHolder.currentRequestAttributes(RequestContextHolder.java:131)
    at org.springframework.web.context.request.AbstractRequestAttributesScope.get(AbstractRequestAttributesScope.java:40)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:328)
    ... 14 more

基于JDK-Dynamic-Proxy-Interface的请求范围bean的堆栈跟踪(proxymode=scopedproxymode.interfaces)

Exception in thread "Thread-16" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'scopedTarget.facebook': 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.
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:342)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.aop.target.SimpleBeanTargetSource.getTarget(SimpleBeanTargetSource.java:33)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:182)
    at $Proxy28.userOperations(Unknown Source)
    at com.example.scopetest.ScopeTestController$PrintingThread.run(ScopeTestController.java:61)
    at java.lang.Thread.run(Thread.java:722)
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.springframework.web.context.request.RequestContextHolder.currentRequestAttributes(RequestContextHolder.java:131)
    at org.springframework.web.context.request.AbstractRequestAttributesScope.get(AbstractRequestAttributesScope.java:40)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:328)
    ... 6 more

Answer 1

好的，通过阅读Spring附带的SimpleThreadScope中的代码，我认为您可以通过使用InheritableThreadLocal来创建SimpleInheritableThreadScope。

然后只需使用一点xml来注册您的自定义范围：

<bean class="org.springframework.beans.factory.config.CustomScopeConfigurer">
      <property name="scopes">
          <map>
              <entry key="thread-inherited">
                  <bean class="org.mael.spring.context.support.SimpleInheritableThreadScope"/>
              </entry>
          </map>
      </property>
  </bean>

这意味着当您创建一个具有线程继承的作用域的bean时，您将可以通过每个线程的一个副本访问这个bean，并且该副本可以在您的线程所产生的线程中使用，即可以在您的请求线程所产生的线程中使用的请求作用域bean。