在Spring批处理中在xml头中写入统计信息

我想编写一个xml文件，并在标题中显示已处理记录的数量和未处理的总数

<?xml version='1.0' encoding='UTF-8'?>
<SettlementReport>
    <GroupHeader>
        <DocumentType>My Report</DocumentType>
        <SettlementInfo>
            <SettlementId>MyReport_20191025</SettlementId>
            <SettlementDate>2019-10-25</SettlementDate>
            <NumOfTransactions>2</NumOfTransactions>
            <ReportTotal>1000</ReportTotal>
        </SettlementInfo>
    </GroupHeader>
    <PaymentInfo>
        <RRN>12345</RRN>
        <VehicleRegistration>AA00AAGP</VehicleRegistration>
        <Province>GP</Province>
        <VPSStatus>Application Submitted to Dept</VPSStatus>
        <SBStatus>Fit for Settlement</SBStatus>
        <ServiceCharge>10.00</ServiceCharge>
        <LicenceFee>402.00</LicenceFee>
        <DeliveryFee>38.00</DeliveryFee>
        <OrderTotal>450.00</OrderTotal>
    </PaymentInfo>
    <PaymentInfo>
        <RRN>12346</RRN>
        <VehicleRegistration>AA00ABGP</VehicleRegistration>
        <Province>GP</Province>
        <VPSStatus>Application Submitted to Dept</VPSStatus>
        <SBStatus>Fit for Settlement</SBStatus>
        <ServiceCharge>10.00</ServiceCharge>
        <LicenceFee>502.00</LicenceFee>
        <DeliveryFee>38.00</DeliveryFee>
        <OrderTotal>550.00</OrderTotal>
    </PaymentInfo>
</SettlementReport>

---

我的问题是如何获得已处理事务的数量，并将它们写入与支付信息相同的文件头中。是否有办法在开始写入之前访问执行信息，因为根据我的设计，这些信息不能在页脚中？

可能重复@MahmoudBenHassine，我已经查看了上面的链接，但他们建议的答案对我不起作用，因为总数不能在页脚中。有没有办法在页眉而不是页脚中进行此操作？没有，因为当时信息不可用。需要读取整个文件才能获得总数。由于该步骤将读取/写入块中的项目，文件内容将被写入，之后无法在页眉中重新插入总计。@BrightDodo您是否找到了一种方法来实现您的目标？可能重复@MahmoudBenHassine我已经查看了上面的链接，但他们建议的答案对我不起作用，因为总计不能在页脚中。有没有办法在页眉而不是页脚中进行此操作？没有，因为当时信息不可用。需要读取整个文件才能获得总数。由于该步骤将以块的形式读取/写入项目，因此文件内容将被写入，并且之后无法在标题中重新插入总计。@BrightDodo您找到了实现预期目标的方法吗？

@StepScope
@Bean
StaxEventItemWriter<PaymentInformation> xmlReportWriter() {
    StaxEventItemWriter<PaymentInformation> xmlFileWriter = new StaxEventItemWriter<>();
    String formattedDate = LocalDateTime.now().format(DateTimeFormatter.ISO_LOCAL_DATE);
    String exportFilePath = "my_report_".concat(formattedDate).concat(".xml");

    xmlFileWriter.setResource(new FileSystemResource(exportFilePath));
    xmlFileWriter.setRootTagName("SettlementReport");
    xmlFileWriter.setMarshaller(paymentInfoMarshaller());
    xmlFileWriter.setHeaderCallback(getSettlementReportHeaderCallBack());
    return xmlFileWriter;
}

@Bean
@StepScope
SettlementReportHeaderCallBack getSettlementReportHeaderCallBack(){
    return new SettlementReportHeaderCallBack(2, BigDecimal.TEN);
}

@Bean
public Step reportStep() {
    return steps.get("settlementReport")
            .<Order, PaymentInformation>chunk(100)
            .reader(reader())
            .processor(processor())
            .writer(xmlReportWriter())
            .build();
}

@Slf4j
@RequiredArgsConstructor
public class SettlementReportHeaderCallBack implements StaxWriterCallback {
    private final int numberOfTransactions;
    private final BigDecimal controlSum;

    @Override
    public void write(XMLEventWriter writer) {
        XMLEventFactory factory = XMLEventFactory.newInstance();
        try {
            writer.add(factory.createStartElement("", "", "GroupHeader"));

            writer.add(factory.createStartElement("", "", "DocumentType"));
            writer.add(factory.createCharacters("Settlement Report"));
            writer.add(factory.createEndElement("", "", "DocumentType"));

            writer.add(factory.createStartElement("", "", "SettlementInfo"));

            writer.add(factory.createStartElement("", "", "SettlementId"));
            writer.add(factory.createCharacters("VAS_VPS_LD_".concat(LocalDateTime.now().format(DateTimeFormatter.BASIC_ISO_DATE))));
            writer.add(factory.createEndElement("", "", "SettlementId"));

            writer.add(factory.createStartElement("", "", "SettlementDate"));
            writer.add(factory.createCharacters(LocalDateTime.now().format(DateTimeFormatter.ISO_LOCAL_DATE)));
            writer.add(factory.createEndElement("", "", "SettlementDate"));

            writer.add(factory.createStartElement("", "", "NumOfTransactions"));
            writer.add(factory.createCharacters(String.valueOf(numberOfTransactions)));
            writer.add(factory.createEndElement("", "", "NumOfTransactions"));

            writer.add(factory.createStartElement("", "", "ReportTotal"));
            writer.add(factory.createCharacters(controlSum.toString()));
            writer.add(factory.createEndElement("", "", "ReportTotal"));

            writer.add(factory.createEndElement("", "", "SettlementInfo"));
            writer.add(factory.createEndElement("", "", "GroupHeader"));
        } catch (XMLStreamException e) {
            log.error("Error writing XML Header: {}", e.getMessage());
            throw new XmlWriterException(e.getMessage());
        }
    }
}