Using json datasource with JasperReports 4.5.1. Get JRExpressionEvalException exception - json

Question

I'm having issues accessing the array from my JSON data source. I'm using jasperreports 4.5.1.
My contact.json file:
{ "Person": { "FirstName": "John", "LastName": "Smith", "Contacts": [ { "Type":
"Cell", "Number": "555-555-5555" }, { "Type": "Home", "Number": "666-666-6666" }
] }
}
My contact.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="contact" language="groovy" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20">
<property name="ireport.zoom" value="2.0"/>
<property name="ireport.x" value="0"/>
<property name="ireport.y" value="0"/>
<subDataset name="Contactdataset">
<queryString language="json">
<![CDATA[]]>
</queryString>
<field name="Type" class="java.lang.String">
<property name="net.sf.jasperreports.json.field.expression" value="Type"/>
</field>
<field name="Number" class="java.lang.String">
<property name="net.sf.jasperreports.json.field.expression" value="Number"/>
</field>
</subDataset>
<queryString language="json">
<![CDATA[]]>
</queryString>
<field name="FirstName" class="java.lang.String">
<property name="net.sf.jasperreports.json.field.expression" value="Person.FirstName"/>
</field>
<field name="LastName" class="java.lang.String">
<property name="net.sf.jasperreports.json.field.expression" value="Person.LastName"/>
</field>
<detail>
<band height="300" splitType="Stretch">
<staticText>
<reportElement x="0" y="0" width="80" height="30"/>
<textElement/>
<text><![CDATA[First Name:]]></text>
</staticText>
<staticText>
<reportElement x="0" y="30" width="80" height="30"/>
<textElement/>
<text><![CDATA[Last Name:]]></text>
</staticText>
<textField>
<reportElement x="80" y="0" width="200" height="30"/>
<textElement/>
<textFieldExpression><![CDATA[$F{FirstName}]]></textFieldExpression>
</textField>
<textField>
<reportElement x="80" y="30" width="200" height="30"/>
<textElement/>
<textFieldExpression><![CDATA[$F{LastName}]]></textFieldExpression>
</textField>
<componentElement>
<reportElement x="130" y="166" width="150" height="23"/>
<jr:list xmlns:jr="http://jasperreports.sourceforge.net/jasperreports/components" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports/components http://jasperreports.sourceforge.net/xsd/components.xsd" printOrder="Vertical">
<datasetRun subDataset="Contactdataset">
<dataSourceExpression><![CDATA[((net.sf.jasperreports.engine.data.JsonDataSource)$P{REPORT_DATA_SOURCE}).subDataSource("Person.Contacts")]]></dataSourceExpression>
</datasetRun>
<jr:listContents height="23" width="150">
<textField>
<reportElement x="27" y="0" width="100" height="17"/>
<textElement/>
<textFieldExpression><![CDATA[$F{Type}]]></textFieldExpression>
</textField>
</jr:listContents>
</jr:list>
</componentElement>
<staticText>
<reportElement x="157" y="150" width="100" height="16"/>
<textElement/>
<text><![CDATA[Type]]></text>
</staticText>
</band>
</detail>
I also tried passing Contactdataset as :
<queryString language="json">
<![CDATA[Person.Contacts]]>
</queryString>
and passed that in the datasourceexpression like:
<dataSourceExpression><![CDATA[((net.sf.jasperreports.engine.data.JsonDataSource)$P{REPORT_DATA_SOURCE}).subDataSource("Contactdataset")]]></dataSourceExpression>
What I am doing wrong? I'm getting the following error:
net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression :
Source text :
((net.sf.jasperreports.engine.data.JsonDataSource)$P{REPORT_DATA_SOURCE}).subDataSource("Person.Contacts")

Answer 1

In JasperReports 4.5.1 there was no subDataSource() method for the JsonDataSource. It was introduced in JasperReports 5.0.4.

Answer 2

As mentioned by #Narcis, the subDataSource() method for the JsonDataSource was introduced in JasperReports 5.0.4. and with this fact, you cannot use it in jasperreports 4.5.1. You should then try creating Main report and a Subreport. Add the field FirstName & LastName in the detail band of Main report and create a Subreport to iterate over the Contacts data. Add this Subreport on the detail band of Main report, select SubReport Poperties: "Use a datasource expression" and set below value for the datasource expression:
new net.sf.jasperreports.engine.data.JsonDataSource(new ByteArrayInputStream($F{Contacts}.toString().getBytes()),"")
In your Subreport, add Type & Number field and it would print the nested array accordingly, for every node of the main array.