Question

我有以下作家类原型：

public class MyWriter extends AbstractItemStreamItemWriter<FieldSet> {
    ...
    @Override
    public void close()
    {
        ...
    {
    ...
}

我的工作由这些@Beans：

定义

    @Bean
    protected Step step(ItemReader<FieldSet> reader, ItemWriter<FieldSet> writer)
    {
        return stepBuilder.get("step")
            .<FieldSet, FieldSet> chunk(chunkSize)
            .reader(reader)
            .writer(writer)
            .listener(this)
            .build();
    }

    @Bean
    protected Job myImportJob(Step step, JobExecutionListener jobExecutionListener)
    {
        return jobBuilder
            .get("myImportJob")
            .listener(jobExecutionListener)
            .start(step)
            .build();
    }

作业是从MQ侦听器触发的，如下所示：

@Autowired
private Job job;

@Autowired
private JobLauncher jobLauncher;

@JmsListener(destination = "queue_name")
public void receiveMessage(TextMessage message) throws JMSException
{
    log.warn("Received message {} with listener {}.", message, this);

    JobParametersBuilder jobParametersBuilder = new JobParametersBuilder();

    // add job parameters here
    ...

    JobParameters jobParameters = jobParametersBuilder.toJobParameters();

    try
    {
        JobExecution jobExecution = jobLauncher.run(job, jobParameters);
        log.trace("jobExecution = " + jobExecution);
    }
    catch (JobExecutionException jee)
    {
        log.warn("Could not run job {}", job);
    }
}

我遇到的问题是MyWriter的close方法被调用两次。每个调用的堆栈跟踪是：

Thread [DefaultMessageListenerContainer-2] (Suspended (breakpoint at line 162 in MyWriter)) 
    MyWriter.close() line: 162  
    MyWriter$$FastClassBySpringCGLIB$$80508a22.invoke(int, Object, Object[]) line: not available    
    MethodProxy.invoke(Object, Object[]) line: 204  
    CglibAopProxy$CglibMethodInvocation.invokeJoinpoint() line: 720 
    CglibAopProxy$CglibMethodInvocation(ReflectiveMethodInvocation).proceed() line: 157 
    DelegatingIntroductionInterceptor.doProceed(MethodInvocation) line: 133 
    DelegatingIntroductionInterceptor.invoke(MethodInvocation) line: 121    
    CglibAopProxy$CglibMethodInvocation(ReflectiveMethodInvocation).proceed() line: 179 
    CglibAopProxy$DynamicAdvisedInterceptor.intercept(Object, Method, Object[], MethodProxy) line: 655  
    MyWriter$$EnhancerBySpringCGLIB$$e345242b.close() line: not available   
    CompositeItemStream.close() line: 85    
    TaskletStep.close(ExecutionContext) line: 305   
    TaskletStep(AbstractStep).execute(StepExecution) line: 271  
--> SimpleStepHandler.handleStep(Step, JobExecution) line: 148  
    SimpleJob(AbstractJob).handleStep(Step, JobExecution) line: 392 
    SimpleJob.doExecute(JobExecution) line: 135 
    SimpleJob(AbstractJob).execute(JobExecution) line: 306  
    SimpleJobLauncher$1.run() line: 135 
    SyncTaskExecutor.execute(Runnable) line: 50 
    SimpleJobLauncher.run(Job, JobParameters) line: 128 
    NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]  
    NativeMethodAccessorImpl.invoke(Object, Object[]) line: 62  
    DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 43  
    Method.invoke(Object, Object...) line: 497  
    AopUtils.invokeJoinpointUsingReflection(Object, Method, Object[]) line: 302 
    ReflectiveMethodInvocation.invokeJoinpoint() line: 190  
    ReflectiveMethodInvocation.proceed() line: 157  
    SimpleBatchConfiguration$PassthruAdvice.invoke(MethodInvocation) line: 127  
    ReflectiveMethodInvocation.proceed() line: 179  
    JdkDynamicAopProxy.invoke(Object, Method, Object[]) line: 208   
    $Proxy105.run(Job, JobParameters) line: not available   
    MyMQListener$$EnhancerBySpringCGLIB$$28277c0e(MyMQListener).receiveMessage(TextMessage) line: 74    
    NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]  
    NativeMethodAccessorImpl.invoke(Object, Object[]) line: 62  
    DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 43  
    Method.invoke(Object, Object...) line: 497  
    InvocableHandlerMethod.doInvoke(Object...) line: 198    
    InvocableHandlerMethod.invoke(Message<?>, Object...) line: 116  
    MessagingMessageListenerAdapter.invokeHandler(Message, Session, Message<?>) line: 90    
    MessagingMessageListenerAdapter.onMessage(Message, Session) line: 66    
    DefaultMessageListenerContainer(AbstractMessageListenerContainer).doInvokeListener(SessionAwareMessageListener, Session, Message) line: 721 
    DefaultMessageListenerContainer(AbstractMessageListenerContainer).invokeListener(Session, Message) line: 681    
    DefaultMessageListenerContainer(AbstractMessageListenerContainer).doExecuteListener(Session, Message) line: 651 
    DefaultMessageListenerContainer(AbstractPollingMessageListenerContainer).doReceiveAndExecute(Object, Session, MessageConsumer, TransactionStatus) line: 315 
    DefaultMessageListenerContainer(AbstractPollingMessageListenerContainer).receiveAndExecute(Object, Session, MessageConsumer) line: 253  
    DefaultMessageListenerContainer$AsyncMessageListenerInvoker.invokeListener() line: 1150 
    DefaultMessageListenerContainer$AsyncMessageListenerInvoker.executeOngoingLoop() line: 1142 
    DefaultMessageListenerContainer$AsyncMessageListenerInvoker.run() line: 1039    
    Thread.run() line: 745

和

Thread [DefaultMessageListenerContainer-2] (Suspended (breakpoint at line 162 in MyWriter)) 
    MyWriter.close() line: 162  
    NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]  
    NativeMethodAccessorImpl.invoke(Object, Object[]) line: 62  
    DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 43  
    Method.invoke(Object, Object...) line: 497  
    DisposableBeanAdapter.invokeCustomDestroyMethod(Method) line: 354   
    DisposableBeanAdapter.destroy() line: 277   
    DisposableBeanAdapter.run() line: 236   
    StepContext.close() line: 213   
    StepSynchronizationManager$1.close(StepContext) line: 53    
    StepSynchronizationManager$1.close(Object) line: 36 
    StepSynchronizationManager$1(SynchronizationManagerSupport<E,C>).release() line: 190    
    StepSynchronizationManager.release() line: 112  
    TaskletStep(AbstractStep).doExecutionRelease() line: 290    
    TaskletStep(AbstractStep).execute(StepExecution) line: 278  
--> SimpleStepHandler.handleStep(Step, JobExecution) line: 148  
    SimpleJob(AbstractJob).handleStep(Step, JobExecution) line: 392 
    SimpleJob.doExecute(JobExecution) line: 135 
    SimpleJob(AbstractJob).execute(JobExecution) line: 306  
    SimpleJobLauncher$1.run() line: 135 
    SyncTaskExecutor.execute(Runnable) line: 50 
    SimpleJobLauncher.run(Job, JobParameters) line: 128 
    NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]  
    NativeMethodAccessorImpl.invoke(Object, Object[]) line: 62  
    DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 43  
    Method.invoke(Object, Object...) line: 497  
    AopUtils.invokeJoinpointUsingReflection(Object, Method, Object[]) line: 302 
    ReflectiveMethodInvocation.invokeJoinpoint() line: 190  
    ReflectiveMethodInvocation.proceed() line: 157  
    SimpleBatchConfiguration$PassthruAdvice.invoke(MethodInvocation) line: 127  
    ReflectiveMethodInvocation.proceed() line: 179  
    JdkDynamicAopProxy.invoke(Object, Method, Object[]) line: 208   
    $Proxy105.run(Job, JobParameters) line: not available   
    MyMQListener$$EnhancerBySpringCGLIB$$28277c0e(MyMQListener).receiveMessage(TextMessage) line: 74    
    NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]  
    NativeMethodAccessorImpl.invoke(Object, Object[]) line: 62  
    DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 43  
    Method.invoke(Object, Object...) line: 497  
    InvocableHandlerMethod.doInvoke(Object...) line: 198    
    InvocableHandlerMethod.invoke(Message<?>, Object...) line: 116  
    MessagingMessageListenerAdapter.invokeHandler(Message, Session, Message<?>) line: 90    
    MessagingMessageListenerAdapter.onMessage(Message, Session) line: 66    
    DefaultMessageListenerContainer(AbstractMessageListenerContainer).doInvokeListener(SessionAwareMessageListener, Session, Message) line: 721 
    DefaultMessageListenerContainer(AbstractMessageListenerContainer).invokeListener(Session, Message) line: 681    
    DefaultMessageListenerContainer(AbstractMessageListenerContainer).doExecuteListener(Session, Message) line: 651 
    DefaultMessageListenerContainer(AbstractPollingMessageListenerContainer).doReceiveAndExecute(Object, Session, MessageConsumer, TransactionStatus) line: 315 
    DefaultMessageListenerContainer(AbstractPollingMessageListenerContainer).receiveAndExecute(Object, Session, MessageConsumer) line: 253  
    DefaultMessageListenerContainer$AsyncMessageListenerInvoker.invokeListener() line: 1150 
    DefaultMessageListenerContainer$AsyncMessageListenerInvoker.executeOngoingLoop() line: 1142 
    DefaultMessageListenerContainer$AsyncMessageListenerInvoker.run() line: 1039    
    Thread.run() line: 745

堆栈中的最后一个公共行是SimpleStepHandler.handleStep(Step, JobExecution) line: 148，用箭头标记。

我目前有一个特殊的类级布尔变量，只存在以确保close方法的内核只运行一次，但这对我来说似乎不太合适。

阅读或写作没有例外或问题。这不是由于跳过或重新启动功能。

如何防止ItemWriter.close（）方法被调用两次？

Answer 1

由于这个错误，我头疼得很厉害。

Spring尝试在使用Java配置时自动推断一个destroyMethod（但在使用XML配置时却不这样做）。要禁用此自动推断，请使用：

from copy import deepcopy
empty = []
for x in range(2):
    empty.append([])
    for y in range(2):
        empty[x].append(False)

status = {k:[] for k in ["a", "b", "c"]}

status["a"] = deepcopy(empty)
status["b"] = deepcopy(empty)
status["c"] = deepcopy(empty)

print(status)
status["a"][0][0] = True
print(status)

现在使用此注释Spring停止两次调用我的方法，并且只会由Spring批处理调用一次。

Spring Batch自定义编写器关闭方法被调用两次（需要特殊处理）

1 个答案: