我使用JesperRports在其中创建了一个包含SubReport的报告，但它不起作用且代码看起来不错。
我得到的警告是：The supplied java.sql.Connection object is null。
这是我的完整代码：
MasterTeste.jrxml
<?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="MasterTeste" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="e976d12d-4c1b-4cfd-900a-6ac502f80b50">
<parameter name="DS" class="java.util.List">
<defaultValueExpression><![CDATA[$F{lstCours}]]></defaultValueExpression>
</parameter>
<queryString>
<![CDATA[]]>
</queryString>
<field name="nom" class="java.lang.String">
<fieldDescription><![CDATA[nom]]></fieldDescription>
</field>
<field name="progres" class="java.lang.String">
<fieldDescription><![CDATA[progres]]></fieldDescription>
</field>
<field name="score" class="java.lang.String">
<fieldDescription><![CDATA[score]]></fieldDescription>
</field>
<field name="lstCours" class="java.util.List">
<fieldDescription><![CDATA[lstCours]]></fieldDescription>
</field>
<detail>
<band height="180" splitType="Stretch">
<staticText>
<reportElement mode="Opaque" x="0" y="3" width="555" height="26" backcolor="#666666" uuid="06a43d96-317c-4a59-bfae-d014050e3955"/>
<text><![CDATA[]]></text>
</staticText>
<staticText>
<reportElement x="3" y="6" width="65" height="20" uuid="7df685f6-8e54-4147-ac6e-52eae09577c0"/>
<textElement>
<font size="15" isBold="true"/>
</textElement>
<text><![CDATA[Section : ]]></text>
</staticText>
<staticText>
<reportElement x="256" y="6" width="68" height="20" uuid="7cbd59f2-280d-4e8f-84db-5a7bf0425596"/>
<textElement>
<font size="15" isBold="true"/>
</textElement>
<text><![CDATA[Progres : ]]></text>
</staticText>
<staticText>
<reportElement x="434" y="6" width="60" height="20" uuid="b666bed5-48c7-4edb-ae70-5b582587e4f6"/>
<textElement>
<font size="15" isBold="true"/>
</textElement>
<text><![CDATA[Score :]]></text>
</staticText>
<textField>
<reportElement x="71" y="6" width="178" height="20" uuid="cb1fa244-3296-40d3-afd9-ee28d29c798d"/>
<textElement>
<font size="13"/>
</textElement>
<textFieldExpression><![CDATA[$F{nom}]]></textFieldExpression>
</textField>
<textField>
<reportElement x="329" y="6" width="57" height="20" uuid="4d667ac4-cd25-4f1f-a1a5-5b354ccc00b9"/>
<textElement>
<font size="13"/>
</textElement>
<textFieldExpression><![CDATA[$F{progres}]]></textFieldExpression>
</textField>
<textField>
<reportElement x="500" y="6" width="55" height="20" uuid="3e771498-10a4-4f4c-9305-cd639de1b4e5"/>
<textElement>
<font size="13"/>
</textElement>
<textFieldExpression><![CDATA[$F{score}]]></textFieldExpression>
</textField>
<subreport>
<reportElement positionType="Float" x="0" y="36" width="555" height="140" isRemoveLineWhenBlank="true" backcolor="#99CCFF" uuid="33184f19-8225-428f-88ba-a488753fd445"/>
<subreportParameter name="DS1">
<subreportParameterExpression><![CDATA[new net.sf.jasperreports.engine.data.JRBeanCollectionDataSource($P{DS})]]></subreportParameterExpression>
</subreportParameter>
<subreportExpression><![CDATA["C:\\reports\\" + "teste.jasper"]]></subreportExpression>
</subreport>
</band>
</detail>
</jasperReport>
Teste.jrxml（子报告）：
<?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="hello" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="15289120-bdf0-4edd-905c-647999c3c0cc">
<style name="table">
<box>
<pen lineWidth="1.0" lineColor="#000000"/>
</box>
</style>
<style name="table_TH" mode="Opaque" backcolor="#00FFFF">
<box>
<topPen lineWidth="0.5" lineColor="#000000"/>
<bottomPen lineWidth="0.5" lineColor="#000000"/>
</box>
</style>
<style name="table_CH" mode="Opaque" backcolor="#C6C6C6">
<box>
<topPen lineWidth="0.5" lineColor="#000000"/>
<bottomPen lineWidth="0.5" lineColor="#000000"/>
</box>
</style>
<style name="table_TD" mode="Opaque" backcolor="#FFFFFF">
<box>
<topPen lineWidth="0.5" lineColor="#000000"/>
<bottomPen lineWidth="0.5" lineColor="#000000"/>
</box>
</style>
<subDataset name="New Dataset 1" uuid="2c012e5d-0895-4ef1-8b47-20fd8c6b281f">
<queryString>
<![CDATA[]]>
</queryString>
<field name="nom" class="java.lang.String"/>
<field name="introComp" class="java.lang.String"/>
<field name="lessComp" class="java.lang.String"/>
<field name="resumComp" class="java.lang.String"/>
<field name="quiz" class="java.lang.String"/>
<field name="progres" class="java.lang.String"/>
</subDataset>
<parameter name="DS1" class="net.sf.jasperreports.engine.data.JRBeanCollectionDataSource"/>
<queryString>
<![CDATA[]]>
</queryString>
<detail>
<band height="151" splitType="Stretch">
<componentElement>
<reportElement key="table" style="table" x="1" y="4" width="555" height="140" isPrintWhenDetailOverflows="true" uuid="1e15cf18-8adf-4bad-9339-04deb8240c82"/>
<jr:table xmlns:jr="http://jasperreports.sourceforge.net/jasperreports/components" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports/components http://jasperreports.sourceforge.net/xsd/components.xsd">
<datasetRun subDataset="New Dataset 1" uuid="5ccdd061-c1c3-46a0-bc92-af14bda9b14a">
<datasetParameter name="REPORT_DATA_SOURCE">
<datasetParameterExpression><![CDATA[$P{DS1}]]></datasetParameterExpression>
</datasetParameter>
</datasetRun>
<jr:column width="99" uuid="faddf5bb-759d-4efc-9a3e-9cf16b8cbda2">
<jr:columnHeader style="table_CH" height="35" rowSpan="1">
<staticText>
<reportElement x="0" y="4" width="56" height="20" uuid="795dac43-0ff0-482c-89a0-7dac3b27d513"/>
<textElement>
<font size="15" isBold="true"/>
</textElement>
<text><![CDATA[Cours]]></text>
</staticText>
</jr:columnHeader>
<jr:detailCell style="table_TD" height="30" rowSpan="1">
<textField>
<reportElement x="3" y="4" width="56" height="20" uuid="195d51a0-9e45-4201-ad67-d3026ce2e72c"/>
<textFieldExpression><![CDATA[$F{nom}]]></textFieldExpression>
</textField>
</jr:detailCell>
</jr:column>
<jr:column width="103" uuid="8a8bc20b-f8b4-45a6-9cbd-68b4a7391426">
<jr:columnHeader style="table_CH" height="35" rowSpan="1">
<staticText>
<reportElement x="0" y="5" width="90" height="20" uuid="795dac43-0ff0-482c-89a0-7dac3b27d513"/>
<textElement>
<font size="15" isBold="true"/>
</textElement>
<text><![CDATA[Introduction]]></text>
</staticText>
</jr:columnHeader>
<jr:detailCell style="table_TD" height="30" rowSpan="1">
<textField>
<reportElement x="3" y="4" width="74" height="20" uuid="195d51a0-9e45-4201-ad67-d3026ce2e72c"/>
<textFieldExpression><![CDATA[$F{introComp}]]></textFieldExpression>
</textField>
</jr:detailCell>
</jr:column>
<jr:column width="87" uuid="fde36038-294c-4987-bd03-734736ddb792">
<jr:columnHeader style="table_CH" height="35" rowSpan="1">
<staticText>
<reportElement x="0" y="5" width="67" height="20" uuid="795dac43-0ff0-482c-89a0-7dac3b27d513"/>
<textElement>
<font size="15" isBold="true"/>
</textElement>
<text><![CDATA[Lesson]]></text>
</staticText>
</jr:columnHeader>
<jr:detailCell style="table_TD" height="30" rowSpan="1">
<textField>
<reportElement x="3" y="4" width="74" height="20" uuid="195d51a0-9e45-4201-ad67-d3026ce2e72c"/>
<textFieldExpression><![CDATA[$F{lessComp}]]></textFieldExpression>
</textField>
</jr:detailCell>
</jr:column>
<jr:column width="90" uuid="51b5dbd4-1bf2-450f-ba8c-f75ea831860b">
<jr:columnHeader style="table_CH" height="35" rowSpan="1">
<staticText>
<reportElement x="0" y="5" width="67" height="20" uuid="795dac43-0ff0-482c-89a0-7dac3b27d513"/>
<textElement>
<font size="15" isBold="true"/>
</textElement>
<text><![CDATA[Resume]]></text>
</staticText>
</jr:columnHeader>
<jr:detailCell style="table_TD" height="30" rowSpan="1">
<textField>
<reportElement x="3" y="4" width="74" height="20" uuid="195d51a0-9e45-4201-ad67-d3026ce2e72c"/>
<textFieldExpression><![CDATA[$F{resumComp}]]></textFieldExpression>
</textField>
</jr:detailCell>
</jr:column>
<jr:column width="87" uuid="657d2155-3e2f-4f41-ba0a-a17a76598491">
<jr:columnHeader style="table_CH" height="35" rowSpan="1">
<staticText>
<reportElement x="0" y="5" width="67" height="20" uuid="795dac43-0ff0-482c-89a0-7dac3b27d513"/>
<textElement>
<font size="15" isBold="true"/>
</textElement>
<text><![CDATA[Quiz]]></text>
</staticText>
</jr:columnHeader>
<jr:detailCell style="table_TD" height="30" rowSpan="1">
<textField>
<reportElement x="3" y="4" width="56" height="20" uuid="195d51a0-9e45-4201-ad67-d3026ce2e72c"/>
<textFieldExpression><![CDATA[$F{quiz}]]></textFieldExpression>
</textField>
</jr:detailCell>
</jr:column>
<jr:column width="87" uuid="d36e39c4-8408-4f2f-865f-787aa3166a7e">
<jr:columnHeader style="table_CH" height="35" rowSpan="1">
<staticText>
<reportElement x="0" y="5" width="67" height="20" uuid="795dac43-0ff0-482c-89a0-7dac3b27d513"/>
<textElement>
<font size="15" isBold="true"/>
</textElement>
<text><![CDATA[Progres]]></text>
</staticText>
</jr:columnHeader>
<jr:detailCell style="table_TD" height="30" rowSpan="1">
<textField>
<reportElement x="3" y="4" width="56" height="20" uuid="195d51a0-9e45-4201-ad67-d3026ce2e72c"/>
<textFieldExpression><![CDATA[$F{progres}]]></textFieldExpression>
</textField>
</jr:detailCell>
</jr:column>
</jr:table>
</componentElement>
</band>
</detail>
</jasperReport>
Java：
public static void main(String[] args) {
List<CoursRapport> coursRapports = new ArrayList<CoursRapport>();
coursRapports.add(new CoursRapport("cours 1", "Complet", "Complet", "Complet", "Complet", "100 %"));
coursRapports.add(new CoursRapport("cours 2", "Complet", "Complet", "Complet", "Complet", "100 %"));
coursRapports.add(new CoursRapport("cours 3", "Complet", "Complet", "Complet", "Complet", "100 %"));
SectionRapport sectRapport = new SectionRapport();
sectRapport.setNom("Sect 1");
sectRapport.setProgres("100%");
sectRapport.setScore("80%");
sectRapport.setLstCours(coursRapports);
List<SectionRapport> lstSectionRapports = new ArrayList<SectionRapport>();
lstSectionRapports.add(sectRapport);
try{
JasperReport jasperReport = JasperCompileManager.compileReport("C:\\reports\\MasterTeste.jrxml");
JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, new HashMap<String, Object>(), new JRBeanCollectionDataSource(lstSectionRapports)); // new JREmptyDataSource()
JasperExportManager.exportReportToPdfFile(jasperPrint, "C:\\ressources\\teste.pdf");
System.out.println("HelloJasper.pdf has been generated!");
} catch (JRException e){
e.printStackTrace();
}
}
当我使用样本报告时它工作正常，但现在subreport部分因上面提到的警告而空了，所以也许我没有正确实现subreport？ / p>
答案 0 :(得分：1)
在子报表中设置whenNoDataType =“AllSectionsNoDetail”（在jasperReport元素上），并将表格元素移动到标题或摘要带。
或者，您可以将新的JREmptyDataSource（）作为主报表中子报表的数据源表达式传递。