Get current resource name using MultiResourceItemReader Spring batch

问题

I am using MultiResourceItemReader in Spring Batch for reading multiple XML files and I want to get current resource.Here is my configuration:

public class MultiFileResourcePartitioner extends MultiResourceItemReader<MyObject> {
    @Override
    public void update(final ExecutionContext pExecutionContext) throws ItemStreamException {
        super.update(pExecutionContext);
        if (getCurrentResource() != null && getCurrentResource().getFilename() != null) {
            System.out.println(\"update:\" + getCurrentResource().getFilename());
        }
    }
}

And my reader:

<bean id=\"myMultiSourceReader\"
   class=\"mypackage.MultiFileResourcePartitioner\">
   <property name=\"resources\" value=\"file:${input.directory}/*.xml\" />

</bean>

The code above read XML files correctly but the method getCurrentResources() return null. By debugging, the batch enter to update method

Please help!

回答1:

There is a specific interface for this problem called ResourceAware: it's purpouse is to inject current resource into objects read from a MultiResourceItemReader.
Check this thread for further information.

回答2:

I tried it with a simple Listener for logging the current resource from a injected {@link MultiResourceItemReader}. Saves the value to the StepExecutionContext.

To get it working with a step scoped MultiResourceItemReader i access the proxy directly, see http://forum.springsource.org/showthread.php?120775-Accessing-the-currently-processing-filename, https://gist.github.com/1582202 and https://jira.springsource.org/browse/BATCH-1831.

public class GetCurrentResourceChunkListener implements ChunkListener, StepExecutionListener {

    private StepExecution stepExecution;
    private Object proxy;
    private final List<String> fileNames = new ArrayList<>();

    public void setProxy(Object mrir) {
        this.proxy = mrir;
    }

    @Override
    public void beforeStep(StepExecution stepExecution) {
        this.stepExecution = stepExecution;
    }

    @Override
    public ExitStatus afterStep(StepExecution stepExecution) {
        return stepExecution.getExitStatus();
    }

    @Override
    public void beforeChunk(ChunkContext cc) {
        if (proxy instanceof Advised) {
            try {
                Advised advised = (Advised) proxy;
                Object obj = advised.getTargetSource().getTarget();
                MultiResourceItemReader mrirTarget = (MultiResourceItemReader) obj;
                if (mrirTarget != null
                        && mrirTarget.getCurrentResource() != null
                        && !fileNames.contains(mrirTarget.getCurrentResource().getFilename())) {
                    String fileName = mrirTarget.getCurrentResource().getFilename();
                    fileNames.add(fileName);
                    String index = String.valueOf(fileNames.indexOf(fileName));
                    stepExecution.getExecutionContext().put("current.resource" + index, fileName);
                }
            } catch (Exception ex) {
                throw new RuntimeException(ex);
            }
        }
    }

    @Override
    public void afterChunk(ChunkContext cc) {
    }

    @Override
    public void afterChunkError(ChunkContext cc) {
    }
}

see https://github.com/langmi/spring-batch-examples-playground for a working example - look for "GetCurrentResource..."

来源：https://stackoverflow.com/questions/22993633/get-current-resource-name-using-multiresourceitemreader-spring-batch

标签

spring-batch

xml