我遇到了从应用程序上下文中提取Spring bean的问题。
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]
如果没有在getBean（）调用中指定的类，我会得到一个ClassCastException（您可以在下面详细介绍）。
InnerThread bean正在初始化为非单例，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。拥有更多Spring经验的人能告诉我这里发生了什么吗？
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;
}
}
APP-context.xml中：
<?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>
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)
答案 0 :(得分：32)
使用
为您的@Configuration课程添加注释
@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>
答案 1 :(得分：25)
再次，在花了好几个小时试图调试之后，我在StackOverflow上发布后立即找到答案。
我从问题中遗漏的一个关键点是InnerThread有一个事务方法（抱歉认为这是无关紧要的）。这是OuterThread和InnerThread之间的重要区别。
请注意
多个部分在运行时折叠为一个统一的自动代理创建器，它应用指定的任何部分（通常来自不同的XML bean定义文件）的最强代理设置。这也适用于和元素。
要明确：使用'proxy-target-class =“true”'，或者元素将强制使用CGLIB proxies来表示所有这三个。
将上述内容添加到我的配置（基于persistance-context.xml，您可以在上面看到加载）行似乎可以解决问题。但是，我认为这可能是一个快速解决方法而不是真正的解决方案。
我认为我在这里遇到了一些更深层次的问题，排名第一的是我觉得Spring像咒骂一样令人困惑。其次，我应该使用Spring's TaskExecutor开始我的线程。我的第三个线程应该实现Runnable而不是扩展Thread（参见下面的SO问题）。
另见
答案 2 :(得分：2)
这只是猜测，但尝试创建一个接口InnerThreadInterface，然后让InnerThread类扩展它。
之后你应该能够做到：
InnerThreadInterface inner = ctx.getBean（“innerThread”，InnerThread.class）;
答案 3 :(得分：1)
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。我确定了ehcache：注释标签是责备...删除以下配置为我解决了这个问题。幸运的是，我能够使用hibernate 2级缓存，而不必使用ehcache声明性缓存。
<ehcache:annotations>
<ehcache:caching id="myCacheModel" cacheName="myCache"/>
<ehcache:flushing id="myFlushModel" cacheNames="myCache" when="after"/>
</ehcache:annotations>
答案 4 :(得分：1)
我遇到了同样的问题：
这只是猜测，但尝试制作 一个接口InnerThreadInterface， 然后让InnerThread类扩展它。 之后你应该能够做到：
我使用这种方式而不是上面发布的方式，它工作正常。不需要将proxy-target-class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");
答案 5 :(得分：1)
解决此问题的一种方法是扩展可运行的界面并创建自己的界面：
public class MyInterface extends Runnable {
// your own method declarations here
void doSomething();
...
}
然后你应该实现你的界面而不是runnable：
@Component("myInterface")
@Scope("prototype")
public class MyInterfaceImpl extends MyInterface {
// your own method declarations here
public void doSomething(){
...
}
// implement run from Runnable Interface
@Transactional
public void run(){
.....
}
...
}
这样可以正常工作：
...
MyInterface mynterface = SpringApplicationContext.getBean("myInterface", MyInterface.class);
myInterface.doSomething();
ExecutorService executor = Executors.newSingleThreadExecutor();
executor.submit(myInterface);
...
答案 6 :(得分：0)
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，代理将完全实现接口，并且转换应该没有问题。
答案 7 :(得分：-1)
创建DAO接口并实现到SERVICE类的DAO接口，并在applicationContext.xml文件中提供SERVICE类的配置详细信息，即spring配置文件，并使用bean id访问bean并引用该实例如此实例化DAO接口的代理对象...它将完美地工作....
答案 8 :(得分：-2)
在我重新启动Idea并重建Maven项目之前，一直存在这个问题。