java - 在非单例 bean 上的 Spring 代理上修复 BeanNotOfRequiredTypeException？

Question

我在从应用程序上下文中提取 Spring bean 时遇到问题。

当我尝试时；

InnerThread instance = (InnerThread) SpringContextFactory.getApplicationContext().getBean("innerThread", InnerThread.class);

我明白了；

org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'innerThread' must be of type [com.generic.InnerThread], but was actually of type [$Proxy26]

如果在 getBean() 调用中没有指定类，我会得到一个 ClassCastException（您可以在下面详细看到）。

InnerThread bean 被初始化为非单例，因为我需要多个实例。InnerThread 类还扩展了 Thread。有趣的是，这个错误出现在 OuterThread 中，它的设置方式与 InnerThread 完全相同。

我试图在下面包含所有相关的代码清单/堆栈跟踪。有更多春季经验的人可以告诉我这里发生了什么吗？

---

代码/配置列表

OuterThread.java 片段：

public class OuterThread extends Thread {
    private Queue<InnerThread> createInnerThreads() {
        Queue<InnerThread> threads = new ArrayBlockingQueue();

        ApplicationContext ctx = SpringContextFactory.getApplicationContext();
        int i = 0;
        for (SearchRule search : searches) {
            logger.debug("Number of times looped " + i++);
            //Seprated lines to get a better sense of what is going on
            Object proxy = ctx.getBean("innerThread", InnerThread.class);
            logger.debug(ReflectionToStringBuilder.toString(proxy));
            logger.debug("proxy.getClass(): " + proxy.getClass());
            logger.debug("proxy.getClass().getClassLoader(): " + proxy.getClass().getClassLoader());
            logger.debug("proxy.getClass().getDeclaringClass(): " + proxy.getClass().getDeclaringClass());
            logger.debug("InnerThread.class.getClassLoader(): " + InnerThread.class.getClassLoader());

            //---Exception here---
            InnerThread cst = (InnerThread) proxy;

            threads.add(cst);
        }
        return threads;
    }

    public static void main(String[] args) throws Exception {
        try {
            OuterThread instance = (OuterThread) SpringContextFactory.getApplicationContext().getBean("outerThread", OuterThread.class);
            instance.run();
        } catch (Exception ex) {
            logger.error("Fatal exception.", ex);
            throw ex;
        }
    }
}

SpringContextFactory.java：

public class SpringContextFactory {
    static final Logger logger = LoggerFactory.getLogger(SpringContextFactory.class);
    private static ApplicationContext ctx;
    private static final String DEFAULT_PATH = "META-INF/app-context.xml";

    public static ApplicationContext getApplicationContext() {
        return getApplicationContext(DEFAULT_PATH);
    }

    public static synchronized ApplicationContext getApplicationContext(String path) {
        if (ctx == null) return createApplicationContext(path);
        else return ctx;
    }

    private static ApplicationContext createApplicationContext(String path) {
        if (logger.isDebugEnabled()) logger.debug("Loading Spring Context...");
        ctx = new ClassPathXmlApplicationContext(path);
        if (logger.isDebugEnabled()) logger.debug("Spring Context Loaded");
        return ctx;
    }
}

应用上下文.xml：

<?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:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

    <!-- persistence context from separate jar -->
    <import resource="persistence-context.xml"/>

    <bean id="outerThread" class="com.generic.OuterThread" scope="prototype"/>
    <bean id="innerThread" class="com.generic.InnerThread" scope="prototype"/>

</beans>

堆栈跟踪

2009-05-08 14:34:37,341 [main] DEBUG com.generic.OuterThread.init(OuterThread.java:59) - Initializing OuterThread object, com.generic.OuterThread@1c8fb4b[em=org.hibernate.ejb.EntityManagerImpl@e2892b,currentTime=java.util.GregorianCalendar[time=1241634874841,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="America/New_York",offset=-18000000,dstSavings=3600000,useDaylight=true,transitions=235,lastRule=java.util.SimpleTimeZone[id=America/New_York,offset=-18000000,dstSavings=3600000,useDaylight=true,startYear=0,startMode=3,startMonth=2,startDay=8,startDayOfWeek=1,startTime=7200000,startTimeMode=0,endMode=3,endMonth=10,endDay=1,endDayOfWeek=1,endTime=7200000,endTimeMode=0]],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2009,MONTH=4,WEEK_OF_YEAR=19,WEEK_OF_MONTH=2,DAY_OF_MONTH=6,DAY_OF_YEAR=126,DAY_OF_WEEK=4,DAY_OF_WEEK_IN_MONTH=1,AM_PM=1,HOUR=2,HOUR_OF_DAY=14,MINUTE=34,SECOND=34,MILLISECOND=841,ZONE_OFFSET=-18000000,DST_OFFSET=3600000],maxConcurrentThreads=5,reconId=3,reportUsername=TEST,useOffset=false,username=removed,uuid=bf61494d-ff96-431c-a41f-1e292d0c9fbe,name={T,h,r,e,a,d,-,1},priority=5,threadQ=<null>,eetop=0,single_step=false,daemon=false,stillborn=false,target=<null>,group=java.lang.ThreadGroup[name=main,maxpri=10],contextClassLoader=sun.misc.Launcher$AppClassLoader@11b86e7,inheritedAccessControlContext=java.security.AccessControlContext@1524d43,threadLocals=<null>,inheritableThreadLocals=java.lang.ThreadLocal$ThreadLocalMap@2cbc86,stackSize=0,nativeParkEventPointer=0,tid=9,threadStatus=0,parkBlocker=<null>,blocker=<null>,blockerLock=java.lang.Object@a68fd8,stopBeforeStart=false,throwableFromStop=<null>,uncaughtExceptionHandler=<null>]
2009-05-08 14:34:37,341 [main] DEBUG org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.doJoinTransaction(ExtendedEntityManagerCreator.java:385) - No local transaction to join
2009-05-08 14:34:37,529 [main] DEBUG com.generic.OuterThread.createInnerThreads(OuterThread.java:139) - Number of times looped 0
2009-05-08 14:34:37,529 [main] DEBUG org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:458) - Creating instance of bean 'searchThread' with merged definition [Root bean: class [com.generic.InnerThread]; scope=prototype; abstract=false; lazyInit=false; autowireCandidate=true; autowireMode=0; dependencyCheck=0; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in class path resource [META-INF/app-context.xml]]
2009-05-08 14:34:37,545 [main] DEBUG com.generic.InnerThread.<init>(InnerThread.java:50) - Constructing InnerThread object, com.generic.InnerThread@1080876[em=<null>,coolScheme=<null>,coolUrl=<null>,date=<null>,error=<null>,millisecondsTaken=0,thresholdMet=false,reconId=0,result=-2,searchId=0,username=<null>,uuid=<null>,name={T,h,r,e,a,d,-,2},priority=5,threadQ=<null>,eetop=0,single_step=false,daemon=false,stillborn=false,target=<null>,group=java.lang.ThreadGroup[name=main,maxpri=10],contextClassLoader=sun.misc.Launcher$AppClassLoader@11b86e7,inheritedAccessControlContext=java.security.AccessControlContext@1524d43,threadLocals=<null>,inheritableThreadLocals=java.lang.ThreadLocal$ThreadLocalMap@3aef16,stackSize=0,nativeParkEventPointer=0,tid=10,threadStatus=0,parkBlocker=<null>,blocker=<null>,blockerLock=java.lang.Object@126c6ea,stopBeforeStart=false,throwableFromStop=<null>,uncaughtExceptionHandler=<null>]
2009-05-08 14:34:37,545 [main] DEBUG org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:203) - Returning cached instance of singleton bean 'entityManagerFactory'
2009-05-08 14:34:37,545 [main] DEBUG org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:203) - Returning cached instance of singleton bean 'org.springframework.transaction.config.internalTransactionAdvisor'
2009-05-08 14:34:37,560 [main] DEBUG org.springframework.transaction.interceptor.AbstractFallbackTransactionAttributeSource.getTransactionAttribute(AbstractFallbackTransactionAttributeSource.java:108) - Adding transactional method [report] with attribute [PROPAGATION_REQUIRED,ISOLATION_DEFAULT]
2009-05-08 14:34:37,560 [main] DEBUG org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.buildAdvisors(AbstractAutoProxyCreator.java:494) - Creating implicit proxy for bean 'searchThread' with 0 common interceptors and 1 specific interceptors
2009-05-08 14:34:37,560 [main] DEBUG org.springframework.aop.framework.JdkDynamicAopProxy.getProxy(JdkDynamicAopProxy.java:113) - Creating JDK dynamic proxy: target source is SingletonTargetSource for target object [com.generic.InnerThread@1080876]
2009-05-08 14:34:37,591 [main] DEBUG com.generic.OuterThread.createInnerThreads(OuterThread.java:141) - $Proxy26@1594a88[h=org.springframework.aop.framework.JdkDynamicAopProxy@1f0cf51]
2009-05-08 14:34:37,591 [main] DEBUG com.generic.OuterThread.createInnerThreads(OuterThread.java:142) - proxy.getClass(): class $Proxy26
2009-05-08 14:34:37,591 [main] DEBUG com.generic.OuterThread.createInnerThreads(OuterThread.java:143) - proxy.getClass().getClassLoader(): sun.misc.Launcher$AppClassLoader@11b86e7
2009-05-08 14:34:37,591 [main] DEBUG com.generic.OuterThread.createInnerThreads(OuterThread.java:144) - proxy.getClass().getDeclaringClass(): null
2009-05-08 14:34:37,591 [main] DEBUG com.generic.OuterThread.createInnerThreads(OuterThread.java:145) - InnerThread.class.getClassLoader(): sun.misc.Launcher$AppClassLoader@11b86e7
2009-05-08 14:34:37,591 [main] ERROR com.generic.OuterThread.run(OuterThread.java:101) - Exception in OuterThread, ending reconciliation.
java.lang.ClassCastException: $Proxy26 cannot be cast to com.generic.InnerThread
    at com.generic.OuterThread.createInnerThreads(OuterThread.java:148)
    at com.generic.OuterThread.run(OuterThread.java:65)
    at com.generic.OuterThread.main(OuterThread.java:170)

---

没有回答我的问题的类似问题

• 自动转换 Spring Bean
• 转换为同一类时发生 ClassCastException。

Answer 1

用注释你的@Configuration类

@EnableAspectJAutoProxy(proxyTargetClass = true) 

您还必须添加以下依赖项：

<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>1.7.2</version>
</dependency> 

Answer 2

Answer 3

解决此问题的一种方法是扩展可运行接口并创建自己的：

public interface MyInterface extends Runnable {
  // your own method declarations here
  void doSomething();
  ...
}

然后你应该实现你的接口而不是runnable：

@Component("myInterface")
@Scope("prototype")
     public class MyInterfaceImpl implements MyInterface {

          // your own method declarations here
          public void doSomething(){
          ...
          }


          // implement run from Runnable Interface
          @Transactional
          public void run(){
                .....
          }

             ...
        }

这将正常工作：

...
    MyInterface mynterface = SpringApplicationContext.getBean("myInterface", MyInterface.class);

    myInterface.doSomething();
  ExecutorService executor = Executors.newSingleThreadExecutor();
    executor.submit(myInterface);
...

Answer 4

这只是一个猜测，但尝试制作一个接口 InnerThreadInterface，然后让 InnerThread 类扩展它。

之后，您应该能够：

InnerThreadInterface 内部 = ctx.getBean("innerThread", InnerThread.class);

Answer 5

即使我引用了 CGLIB 并使用了 proxy-target-class="true" 设置，我也遇到了这个问题。我确定 ehcache:annotation 标签是罪魁祸首...删除以下配置为我解决了这个问题。幸运的是，我能够使用休眠级别 2 缓存，而不必使用 ehcache 声明式缓存。

<ehcache:annotations>
    <ehcache:caching id="myCacheModel" cacheName="myCache"/>
    <ehcache:flushing id="myFlushModel" cacheNames="myCache" when="after"/>
</ehcache:annotations> 

Answer 6

处理这个问题的另一种方法是实现一个接口并从spring请求接口，代理将完全实现该接口，并且强制转换应该没有问题。

Answer 7

我有同样的问题：

这只是一个猜测，但尝试制作一个接口 InnerThreadInterface，然后让 InnerThread 类扩展它。之后，您应该能够：

我使用这种方式而不是上面发布的内容，并且效果很好。无需将代理目标类设置为 true，这需要更多不在我的类路径中的库。

InnerThreadInterface inner = (InnerThreadInterface)ctx.getBean("innerThread");

Answer 8

创建DAO接口并实现SERVICE类的DAO接口，并在applicationContext.xml文件即spring配置文件中提供SERVICE类的配置细节，并使用bean id访问bean并引用so实例化代理的实例反对DAO接口......它会工作得很好......

Answer 9

在我重新启动 Idea 并重建 Maven 项目之前，一直存在这个问题。