我使用TIBCO Jaspersoft Studio创建了一个包含三个子报表的主报表。当每个子报表返回至少一个非空白值时，主报表将按预期工作。当仅一个子报表仅返回空白值时，由于声明为空，因此不会生成预览的文档
为了避免返回值设置为null的问题，请在每个字段的属性框中将所有文本字段设置为“如果NULL则空白”
主报告的三个子报告和文本字段在其.jrxml中定义如下
<pageHeader>
<band height="113">
<subreport>
<reportElement x="0" y="0" width="538" height="110" uuid="4fbe1f2c-d89c-4217-8e15-65439f745ef4"/>
<subreportParameter name="encounterID">
<subreportParameterExpression><![CDATA[$P{encounterID}]]></subreportParameterExpression>
</subreportParameter>
<connectionExpression><![CDATA[$P{REPORT_CONNECTION}]]></connectionExpression>
<subreportExpression><![CDATA["EncounterRpt_Top.jasper"]]></subreportExpression>
</subreport>
</band>
</pageHeader>
<detail>
<band height="98">
<property name="com.jaspersoft.studio.layout" value="com.jaspersoft.studio.editor.layout.spreadsheet.SpreadsheetLayout"/>
<textField isStretchWithOverflow="true">
<reportElement stretchType="ElementGroupHeight" x="0" y="0" width="538" height="98" uuid="47bd7997-b492-4a77-bb01-3e6303af9e58"/>
<textElement textAlignment="Justified" markup="html"/>
<textFieldExpression><![CDATA[$F{dtcmts}]]></textFieldExpression>
</textField>
<break>
<reportElement x="0" y="0" width="97" height="1" isPrintWhenDetailOverflows="true" uuid="4b468d03-feac-4678-b3ac-49a88b154e8a"/>
</break>
</band>
<band height="101">
<subreport>
<reportElement x="0" y="0" width="538" height="100" uuid="7e83e8e9-3e68-4897-b01d-51c6f8f78acb"/>
<subreportParameter name="encounterID">
<subreportParameterExpression><![CDATA[$P{encounterID}]]></subreportParameterExpression>
</subreportParameter>
<connectionExpression><![CDATA[$P{REPORT_CONNECTION}]]></connectionExpression>
<subreportExpression><![CDATA["VitalSignsRpt.jasper"]]></subreportExpression>
</subreport>
</band>
<band height="102">
<subreport>
<reportElement x="0" y="0" width="538" height="100" uuid="7e83e8e9-3e68-4897-b01d-51c6f8f78acb"/>
<subreportParameter name="encounterID">
<subreportParameterExpression><![CDATA[$P{encounterID}]]></subreportParameterExpression>
</subreportParameter>
<connectionExpression><![CDATA[$P{REPORT_CONNECTION}]]></connectionExpression>
<subreportExpression><![CDATA["LocationSurveyRpt.jasper"]]></subreportExpression>
</subreport>
</band>
</detail>
最后一个子报表的字段定义如下（注意第二行上的isBlankWhenNull =“ true”）
...
<style name="Data Style" mode="Transparent" forecolor="#000000" backcolor="#FFFFFF" hTextAlign="Center" vTextAlign="Middle"
pattern="" isBlankWhenNull="true" fontSize="12" isBold="false">
<!-- Data Style is used by the details container -->
</style>
<style name="Header Style" mode="Opaque" forecolor="#FFFFFF" backcolor="#1976D2" hTextAlign="Center" vTextAlign="Middle"
pattern="" fontSize="13" isBold="true">
<!-- Header Style is used by the detail container -->
</style>
<parameter name="encounterID" class="java.lang.Integer" evaluationTime="Early">
<!-- used by the query immediately below -->
</parameter>
<queryString>
<![CDATA[SELECT sv.survey_name as svnm, ct.composite_score as ctcs, ct.secondary_score as ctss,
ct.subscores as ctsb, ct.encounter_id as ctei FROM client_surveys ct
INNER JOIN surveys sv ON ct.survey_id = sv.survey_id
WHERE ct.encounter_id = $P{encounterID}]]>
</queryString>
<field>
<!-- Declarations of the field tags -->
</field>
<background>
<band splitType="Stretch"/>
</background>
<pageHeader>
<!-- Printing of the report's name is defined here -->
</pageHeader>
<columnHeader>
<!-- Column names are printed here -->
<band height="30" splitType="Stretch">
<property name="com.jaspersoft.studio.layout" value="com.jaspersoft.studio.editor.layout.spreadsheet.SpreadsheetLayout"/>
<staticText>
<reportElement style="Header Style" x="0" y="0" width="120" height="30" uuid="c10584b8-98bf-4e36-bf59-3324afe8dbb9"/>
<text><![CDATA[Survey Name]]></text>
</staticText>
<staticText>
<reportElement style="Header Style" x="120" y="0" width="140" height="30" uuid="331f69f5-9a55-4567-8dab-4371491e78d2"/>
<text><![CDATA[Composite Score]]></text>
</staticText>
<staticText>
<reportElement style="Header Style" x="260" y="0" width="140" height="30" uuid="a75588dc-be3f-4359-b2ac-84397653fd93"/>
<text><![CDATA[Secondary Score]]></text>
</staticText>
<staticText>
<reportElement style="Header Style" x="400" y="0" width="130" height="30" uuid="50726655-fc62-4496-b1a3-75c08d0bc24e"/>
<text><![CDATA[Subscores]]></text>
</staticText>
</band>
</columnHeader>
<detail>
<!-- row values, if any, are printed here -->
<band height="30" splitType="Stretch">
<property name="com.jaspersoft.studio.layout" value="com.jaspersoft.studio.editor.layout.spreadsheet.SpreadsheetLayout"/>
<textField>
<reportElement style="Data Style" x="0" y="0" width="120" height="30" uuid="f15948f3-599a-4e73-9b42-00880da0a64e"/>
<textFieldExpression><![CDATA[$F{svnm}]]></textFieldExpression>
</textField>
<textField>
<reportElement style="Data Style" x="120" y="0" width="140" height="30" uuid="42d3b12d-73e1-4fd9-ac9e-e2b5469e1157"/>
<textFieldExpression><![CDATA[$F{ctcs}]]></textFieldExpression>
</textField>
<textField>
<reportElement style="Data Style" x="260" y="0" width="140" height="30" uuid="3024d30f-829d-42fa-8adc-2e9f7ebb26e5"/>
<textFieldExpression><![CDATA[$F{ctss}]]></textFieldExpression>
</textField>
<textField>
<reportElement style="Data Style" x="400" y="0" width="130" height="30" uuid="bff07050-bdb8-4760-8ebf-3c25dbb9b1ce"/>
<textFieldExpression><![CDATA[$F{ctsb}]]></textFieldExpression>
</textField>
</band>
</detail>
...
如开头所述，我希望每次发送请求时都打印我的主报告，而不管子报告返回的值如何。如果子报表仅返回空白值，则应从主报表中省略该报表。现在，即使子报表返回了空白值，即使其他报表返回了信息，主报表也被声明为空
是否有一个标签指示主报表在子报表仅返回空白值时忽略子报表？也许是“ ignoreWhenBlank”或其他名称？如果没有，我该怎么办