如何将主报表数据源传递给子报表（JasperReports）？

Question

I am trying to generate a JasperReport PDF with subreports but I can't access the JRBeanCollectionDataSource (coming from a List) passed as parameter to the main report. Or rather, I just get a blank subreport. I expect to be looping of some sort since I am passing a JRBeanCollectionDataSource.

This is my current code:

Java code:

@PostMapping(path = "/generate-contract", consumes = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity < byte[] > report(
    @RequestBody Contract contract) {

    Map<String, Object> params = new HashMap<>();

    // add params to the MASTER REPORT
    params.put("farmName", contract.getFarmName());
    params.put("farmLogo", contract.getFarmLogo());

    // create a JRBeanCollectionDataSource of the List<Signatory> list
    JRBeanCollectionDataSource signatoriesListSubreportDataSource = new JRBeanCollectionDataSource(contract.getSignatoriesList());

    // add it as parameters to be read by the master report
    params.put("signatoriesListSubreportDataSource", signatoriesListSubreportDataSource);

    byte[] bytes = reportService.generatePDFReport("my-master-report", params);

    return ResponseEntity
        .ok()
        .header("Content-Type", "application/pdf; charset=UTF-8")
        .header("Content-Disposition", "inline; filename=\"" + contract.getFarmName() + ".pdf\"")
        .body(bytes);
}

I am calling a .generatePDF() method where it actually compiles the master report and the subreport as well. I don't know if this is accurate though

@Override
    public byte[] generatePDFReport(String inputFileName, Map<String, Object> params) {
        return generatePDFReport(inputFileName, params, new JREmptyDataSource());
    } // this is where it first goes through

@Override
public byte[] generatePDFReport(String inputFileName,
    Map <String, Object> params,
    JRDataSource dataSource) { // then proceeds to this method, creating a blank dataSource

    byte[] bytes = null;
    JasperReport jasperReport = null;
    try (ByteArrayOutputStream byteArray = new ByteArrayOutputStream()) {
        // Check if a compiled report exists
        if (storageService.jasperFileExists(inputFileName)) {
            jasperReport = (JasperReport) JRLoader
                .loadObject(storageService.loadJasperFile(inputFileName));
        }

        String mySignatoriesSubReportFileName = "my-subreport-file-name-here";

        // Compile report from source and save
        String jrxml = storageService.loadJrxmlFile(inputFileName);
        String mySubReport = storageService.loadJrxmlFile(mySignatoriesSubReportFileName);

        // add logs of master report + subreport here
        log.info("{} loaded. Compiling report", jrxml);
        log.info("{} loaded. Compiling report", paiwiSignatoriesSubReport);

        params.put("SUBREPORT_DIR", FileSystemUtil.rootLocation.toString() + "\\");

        // compile the master report together with the subreports
        jasperReport = JasperCompileManager.compileReport(jrxml); // master report
        JasperReport compiledMySubReport = JasperCompileManager.compileReport(mySubReport); // sub-report

        // Save compiled report. Compiled report is loaded next time
        JRSaver.saveObject(jasperReport,
            storageService.loadJasperFile(inputFileName));

        JRSaver.saveObject(compiledMySubReport,
            storageService.loadJasperFile(mySignatoriesSubReportFileName));

        JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, params,
            dataSource);
        bytes = JasperExportManager.exportReportToPdf(jasperPrint);
    } catch (JRException | IOException e) {
        e.printStackTrace();
        log.error("Encountered error when loading jasper file", e);
    }

    return bytes;
}

This is what my master-report.jrxml looks like:

<?xml version="1.0" encoding="UTF-8"?>
<jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="Autogen-contract" pageWidth="612" pageHeight="1008" columnWidth="540" leftMargin="36" rightMargin="36" topMargin="36" bottomMargin="36" whenResourceMissingType="Error" uuid="4d5cd764-f78c-4d28-b2cc-4dadc9e584a1">

    <!-- Location of the compiled subreport. -->
    <parameter name="SUBREPORT_DIR" class="java.lang.String"/>

    <!-- For data source of sub-reports -->
    <parameter name="mySignatoriesListSubReportDataSource" isForPrompting="true" class="net.sf.jasperreports.engine.data.JRBeanCollectionDataSource"/>

    <!-- This one works as of the master report -->
    <parameter name="farmName" class="java.lang.String"/>

    <!-- More details of the master report here.. -->

    <textField>
        <reportElement key="" x="135" y="120" width="270" height="20" isRemoveLineWhenBlank="true" uuid="2974af73-36ae-4781-a7b1-1b0a4a498c5c"/>
        <textElement textAlignment="Center" verticalAlignment="Middle">
            <font fontName="Times New Roman" size="12" isBold="true"/>
        </textElement>
        <textFieldExpression><![CDATA[java.lang.String.format("%s", $P{farmName})]]></textFieldExpression>
    </textField>

    <subreport>
        <reportElement x="1" y="520" width="537" height="20" uuid="fcf375d6-3935-42c9-bc81-1448e6f03ebf"/>
        <dataSourceExpression><![CDATA[$P{mySignatoriesListSubReportDataSource}]]></dataSourceExpression>
        <subreportExpression class="java.lang.String"><![CDATA[$P{SUBREPORT_DIR} + "my-subreport.jasper"]]></subreportExpression>
    </subreport>

    <!-- More details of the master report here.. -->

</jasperReport>

This is what my-subreport.jrxml looks like:

<?xml version="1.0" encoding="UTF-8"?>
<!-- Created with Jaspersoft Studio version 6.5.1.final using JasperReports Library version 6.5.1  -->
<jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="paiwi-signatories-subreport" pageWidth="612" pageHeight="792" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="55585643-052e-4eee-9632-3c9b06dbec8f">
    <subDataset name="Dataset1" uuid="01eaeaca-361c-429f-9e71-e974b4f2beda">
        <queryString>
            <![CDATA[]]>
        </queryString>
    </subDataset>

    <queryString>
        <![CDATA[]]>
    </queryString>

    <!-- I have a name and address in the Signatory object I passed as a list of Data Source.. -->
    <!-- But this doesn't work.. or atleast it doesn't iterate anything -->
    <field name = "name" class = "java.lang.String"/>
    <field name = "address" class = "java.lang.String"/>

    <detail>
        <band height="24" splitType="Stretch">
            <textField>
                <reportElement x="0" y="0" width="140" height="20" uuid="5f357ce5-9928-4657-98f7-c7eace9b9e84"/>
                <textElement verticalAlignment="Middle">
                    <font fontName="Times New Roman" size="12"/>
                </textElement>
                <textFieldExpression><![CDATA[$F{name}]]></textFieldExpression>
            </textField>
            <textField>
                <reportElement x="140" y="0" width="400" height="20" uuid="0390ae27-e46b-4bb4-87d0-83d59abfc22e"/>
                <textElement verticalAlignment="Middle">
                    <font fontName="Times New Roman" size="12"/>
                </textElement>
                <textFieldExpression><![CDATA[$F{address}]]></textFieldExpression>
            </textField>
        </band>
    </detail>
</jasperReport>

I can't access the fields in the sub-report, I don't even know if the parameter farmSignatoriesListSubReportDataSource in the master-report.xml actually goes through and enters the subreport as a valid data source.

Answer 1

If You want to pass the report parameter to subreport then use a subreportParameter tag like below.

<subreport>
        <reportElement x="-12" y="0" width="553" height="110" uuid="e012100d-4c24-468f-9d97-57cda4a0d64a"/>
                <subreportParameter name="cou_ID">
                    <subreportParameterExpression><![CDATA[$P{mySignatoriesListSubReportDataSource}]]></subreportParameterExpression>
                </subreportParameter>
                <connectionExpression><![CDATA[$P{REPORT_CONNECTION}]]></connectionExpression>
                <subreportExpression><![CDATA["my-subreport.jasper"]]></subreportExpression>
</subreport>

I hope it's helpful.

Answer 2

First you add a subreport to a main report. Define parameter in main report which you will set farmSignatoriesListSubReportDataSource at first.

Click the subreport you added open properties sub report tab and open edit parameters. There you will need to add a parameter , give a name to parameter of subreport , and as parameter expression select parameter from the main report which you've already set before. Then you will have your fields at subreport.