我有一个需要动态加载某些适配器的应用程序。这些适配器中的一些被编译到应用程序中，而某些则在运行时提供。有了适配器后，我想在其上调用Adapt(OrderToolRequest，Object)方法。
我的问题是，当类在应用程序中时，我可以使它工作。但是，对于第三方适配器，我可以动态加载运行时提供的类，但无法弄清楚如何调用该方法。我在OrderToolResponse上收到“找不到类”错误。我试图通过让所有适配器实现接口和强制转换，以及通过简单地使用反射来获取方法来做到这一点。
我假设这在某种程度上与不同的类加载器有关，但是我不足以解决该问题。谁能指出我正确的方向？
在以下代码中，一切正常，直到调用getMethod()为止。如果我们在应用程序中找到该类，则此操作成功。如果该类是由URLClassLoader加载的，则会引发未找到类的错误
Class<?> cls = null;
try
{
// #1
cls = Class.forName( adapterName );
}
catch ( ClassNotFoundException e )
{
File file = new File( "Adapters" );
URL url = file.toURI().toURL();
URL[] urls = new URL[]{ url };
URLClassLoader loader = new URLClassLoader( urls );
try
{
// #2
cls = loader.loadClass( adapterName );
}
finally
{
loader.close();
}
}
Constructor<?> constructor = cls.getConstructor();
Object instance = constructor.newInstance();
// #3 THE PROBLEM OCCURS HERE. SUCCEEDS IF LOADED BY #1, BUT FAILS IF LOADED
// BY #2.
Method adaptMethod = cls.getMethod( "adapt", OrderToolRequest.class, Object.class );
...invoke the method, etc.
编辑以更全面地解释
如果该类由语句Class.forName(adapterName)加载，则没有问题。
如果该类是由loader.loadClass(adapterName)加载的，则存在问题。
如果我将代码更改为:
Method adaptMethod = null;
try
{
adaptMethod = cls.getMethod( "adapt", OrderToolRequest.class, Object.class );
}
catch ( Error e )
{
log.error( "Didn't work" );
}
并在日志记录语句上设置断点，然后:
“com / ca / eai / model / canonical / OrderToolResponse”
编辑＃2堆栈跟踪。我必须截断超过30,000个字符
您会看到由ClassNotFoundException引起的NoClassDefFoundError。
java.lang.NoClassDefFoundError: com/ca/eai/model/canonical/OrderToolResponse
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2442)
at java.lang.Class.getMethod0(Class.java:2685)
at java.lang.Class.getMethod(Class.java:1620)
at com.ca.eai.esb.transformer.orchestration.AdapterInvokingTransformer.findAdapter(AdapterInvokingTransformer.java:73)
at com.ca.eai.esb.transformer.orchestration.AdapterInvokingTransformer.transformMessage(AdapterInvokingTransformer.java:106)
at org.mule.transformer.AbstractMessageTransformer.transform(AbstractMessageTransformer.java:145)
at org.mule.transformer.AbstractMessageTransformer.transform(AbstractMessageTransformer.java:93)
at org.mule.DefaultMuleMessage.transformMessage(DefaultMuleMessage.java:1455)
at org.mule.DefaultMuleMessage.applyAllTransformers(DefaultMuleMessage.java:1363)
at org.mule.DefaultMuleMessage.applyTransformers(DefaultMuleMessage.java:1341)
at org.mule.DefaultMuleMessage.applyTransformers(DefaultMuleMessage.java:1333)
at org.mule.transformer.AbstractTransformer.process(AbstractTransformer.java:123)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorNotificationExecutionInterceptor.execute(MessageProcessorNotificationExecutionInterceptor.java:61)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.chain.DefaultMessageProcessorChain.doProcess(DefaultMessageProcessorChain.java:95)
at org.mule.processor.chain.AbstractMessageProcessorChain.process(AbstractMessageProcessorChain.java:70)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper.doProcess(InterceptingChainLifecycleWrapper.java:54)
at org.mule.processor.chain.AbstractMessageProcessorChain.process(AbstractMessageProcessorChain.java:70)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper.access$001(InterceptingChainLifecycleWrapper.java:26)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper$1.process(InterceptingChainLifecycleWrapper.java:70)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorNotificationExecutionInterceptor.execute(MessageProcessorNotificationExecutionInterceptor.java:61)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper.process(InterceptingChainLifecycleWrapper.java:65)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorNotificationExecutionInterceptor.execute(MessageProcessorNotificationExecutionInterceptor.java:61)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.chain.DefaultMessageProcessorChain.doProcess(DefaultMessageProcessorChain.java:95)
at org.mule.processor.chain.AbstractMessageProcessorChain.process(AbstractMessageProcessorChain.java:70)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper.doProcess(InterceptingChainLifecycleWrapper.java:54)
at org.mule.processor.chain.AbstractMessageProcessorChain.process(AbstractMessageProcessorChain.java:70)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper.access$001(InterceptingChainLifecycleWrapper.java:26)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper$1.process(InterceptingChainLifecycleWrapper.java:70)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorNotificationExecutionInterceptor.execute(MessageProcessorNotificationExecutionInterceptor.java:61)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper.process(InterceptingChainLifecycleWrapper.java:65)
at org.mule.routing.AbstractSelectiveRouter.processEventWithProcessor(AbstractSelectiveRouter.java:312)
at org.mule.routing.AbstractSelectiveRouter.routeWithProcessors(AbstractSelectiveRouter.java:302)
at org.mule.routing.AbstractSelectiveRouter.process(AbstractSelectiveRouter.java:202)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorNotificationExecutionInterceptor.execute(MessageProcessorNotificationExecutionInterceptor.java:61)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.chain.DefaultMessageProcessorChain.doProcess(DefaultMessageProcessorChain.java:95)
at org.mule.processor.chain.AbstractMessageProcessorChain.process(AbstractMessageProcessorChain.java:70)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.AbstractInterceptingMessageProcessorBase.processNext(AbstractInterceptingMessageProcessorBase.java:106)
at org.mule.interceptor.AbstractEnvelopeInterceptor.process(AbstractEnvelopeInterceptor.java:55)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorNotificationExecutionInterceptor.execute(MessageProcessorNotificationExecutionInterceptor.java:61)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.AbstractInterceptingMessageProcessorBase.processNext(AbstractInterceptingMessageProcessorBase.java:106)
at org.mule.processor.AsyncInterceptingMessageProcessor.process(AsyncInterceptingMessageProcessor.java:101)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorNotificationExecutionInterceptor.execute(MessageProcessorNotificationExecutionInterceptor.java:61)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.chain.DefaultMessageProcessorChain.doProcess(DefaultMessageProcessorChain.java:95)
at org.mule.processor.chain.AbstractMessageProcessorChain.process(AbstractMessageProcessorChain.java:70)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.AbstractInterceptingMessageProcessorBase.processNext(AbstractInterceptingMessageProcessorBase.java:106)
at org.mule.interceptor.AbstractEnvelopeInterceptor.process(AbstractEnvelopeInterceptor.java:55)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorNotificationExecutionInterceptor.execute(MessageProcessorNotificationExecutionInterceptor.java:61)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.AbstractInterceptingMessageProcessorBase.processNext(AbstractInterceptingMessageProcessorBase.java:106)
at org.mule.processor.AbstractFilteringMessageProcessor.process(AbstractFilteringMessageProcessor.java:44)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorNotificationExecutionInterceptor.execute(MessageProcessorNotificationExecutionInterceptor.java:61)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.AbstractInterceptingMessageProcessorBase.processNext(AbstractInterceptingMessageProcessorBase.java:106)
at org.mule.construct.AbstractPipeline$1.process(AbstractPipeline.java:112)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorNotificationExecutionInterceptor.execute(MessageProcessorNotificationExecutionInterceptor.java:61)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.chain.DefaultMessageProcessorChain.doProcess(DefaultMessageProcessorChain.java:95)
at org.mule.processor.chain.AbstractMessageProcessorChain.process(AbstractMessageProcessorChain.java:70)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper.doProcess(InterceptingChainLifecycleWrapper.java:54)
at org.mule.processor.chain.AbstractMessageProcessorChain.process(AbstractMessageProcessorChain.java:70)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper.access$001(InterceptingChainLifecycleWrapper.java:26)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper$1.process(InterceptingChainLifecycleWrapper.java:70)
at org.mule.execution.ExceptionToMessagingExceptionExecutionInterceptor.execute(ExceptionToMessagingExceptionExecutionInterceptor.java:27)
at org.mule.execution.MessageProcessorNotificationExecutionInterceptor.execute(MessageProcessorNotificationExecutionInterceptor.java:61)
at org.mule.execution.MessageProcessorExecutionTemplate.execute(MessageProcessorExecutionTemplate.java:47)
at org.mule.processor.chain.InterceptingChainLifecycleWrapper.process(InterceptingChainLifecycleWrapper.java:65)
at org.mule.construct.Flow$1.process(Flow.java:74)
at org.mule.construct.Flow$1.process(Flow.java:69)
at org.mule.execution.ExecuteCallbackInterceptor.execute(ExecuteCallbackInterceptor.java:20)
at org.mule.execution.HandleExceptionInterceptor.execute(HandleExceptionInterceptor.java:34)
at org.mule.execution.HandleExceptionInterceptor.execute(HandleExceptionInterceptor.java:18)
at org.mule.execution.BeginAndResolveTransactionInterceptor.execute(BeginAndResolveTransactionInterceptor.java:58)
at org.mule.execution.SuspendXaTransactionInterceptor.execute(SuspendXaTransactionInterceptor.java:54)
at org.mule.execution.RethrowExceptionInterceptor.execute(RethrowExceptionInterceptor.java:32)
at org.mule.execution.RethrowExceptionInterceptor.execute(RethrowExceptionInterceptor.java:17)
at org.mule.execution.ErrorHandlingExecutionTemplate.execute(ErrorHandlingExecutionTemplate.java:63)
at org.mule.execution.ErrorHandlingExecutionTemplate.execute(ErrorHandlingExecutionTemplate.java:34)
at org.mule.construct.Flow.process(Flow.java:68)
...SOME STUFF REMOVED HERE...
Caused by: java.lang.ClassNotFoundException: com.ca.eai.model.canonical.OrderToolResponse
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 260 more
最佳答案
不要关闭装载器。 Javadoc:
关闭此URLClassLoader，使其不再可用于加载
此加载程序定义的新类或资源。